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METAL INJECTION LIVECAST #554 - Rob's Nolita

We kick things off talking about the Rage Against the Machine reunion. We then discuss the summer touring season and...

The post METAL INJECTION LIVECAST #554 - Rob's Nolita appeared first on Metal Injection.



  • Metal Injection Livecast

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9 Convincing Reasons Why Designers Should Pursue Personal Projects

Web designers have skills and expertise that open up a whole world of possibilities. Many designers and developers choose to pursue personal projects in their own time, which can be a nice change of...

Click through to read the rest of the story on the Vandelay Design Blog.




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Top Construction Projects in the World

Highlighting some of humanity’s biggest construction achievements is the 10 of the Top Construction Projects in the World informational infographic from 53 Quantum.

Human societies have always looked to build the biggest and best monuments to their ingenuity, resources and craftsmanship. From the Empire State Building, to the Eiffel Tower, and the Great Pyramids of Giza to the Great Wall of China, we’ve always looked to build the biggest and best. Mind blowing historic building projects now litter travel-minded folks bucket lists everywhere, and they make up a huge part of the historic tapestry.

But it’s 2019 now. We need to talk about the Burj Khalifas and Libyan Irrigation projects of the world. For the first time in history, there are societies wealthy, powerful, and most importantly, cohesive enough to build spectacularly huge projects. By working together with our geographical neighbours, we’ve been able to give the world some truly unbelievable, innovative projects. The International Space Station leaps to mind as a collaboration between nations.

With so many stunning projects continually on the go around the planet, we at 53 Quantum thought it’d be an idea to put together a quick infographic of ten of the biggest and best. Of course, there’ll be examples we missed and things we left off, because how do you compare a massive railway restoration and modernisation with a super skyscraper project? Apples and oranges!

Nevertheless, here are ten of the world’s most impressive construction projects.

Although I like the infographic, this design falls short in a few areas.

  • Where’s the Data Visualization? The biggest missed opportunity in this design is that the data isn’t visualized. You want readers to understand how big or how expensive these projects were, you need a visualization that puts that into context!

  • Nice illustrations, but that isn’t enough. Most of the impact of the size and scale of these projects is lost because it’s buried in the text.

  • A map of the locations would be nice.

  • Is there any logic to the order of these projects in the infographic? Readers will look through the list from top-to-bottom in order. They’re not sorted by cost or on a timeline.

Thanks to David for submitting the link!





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Jetty




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Jesse Chehak, Near Big Water

Jesse Chehak
Near Big Water, Utah, 2010
Website - JesseChehak.com

Born in Tarzana, California, Jesse Chehak studied photography and Art History at Sarah Lawrence College and is currently pursuing a MFA at the University of Arizona. Chehak has exhibited his large format prints in galleries and project spaces including Bruce Silverstein (New York), Danese (New York) and the Durham Art Guild (Durham, North Carolina.) He is currently seeking funding to publish his first monograph, Fool's Gold, and a gallery to exhibit and distribute the completed print edition. In 2005, Chehak joined M.A.P. and began executing commercial campaigns and editorial features for clients, including The New York Times, Wallpaper*, Newsweek, GQ, Ogilvy & Mather, Saatchi & Saatchi, Digitas, and others. Chehak has received notable attention for his work, including PDN30 in 2005, The Magenta Foundation's Flash Forward in 2007, a Baum Nomination in 2008, and AP25. He lives in Tucson and Los Angeles.




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Surf Jæren

Yesterday turned out to be a crisp, sunny, minus 5 degrees day with an awesome swell. I took the Mavic out for a spin before a 2 hour session at Steinen.




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Managing Your Money After a Brain Injury

Managing money is complicated, especially for people with a brain injury who may have trouble remembering what they spent or creating a budget. Adam shares some tips from online banking to keeping a spending journal.




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Every Journey Starts with That First Step, Especially with TBI and/or PTSD

Adam says that like drill and ceremony and calling cadence, which start with a first step, so does recovery from a brain injury and/or PTSD.




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At College, Move Beyond the Stigma of Asking for Help After a Brain Injury

If extra time on a test or memory aids can make life easier during college, why not use them? Adam talks about moving past the "stigma" of using disability services and getting the help you need to succeed in college.




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Troops to receive Purple Hearts for injuries during Iranian missile barrage on al-Asad airbase in Iraq

There will be Purple Hearts awarded to troops injured during the Jan. 8 Iranian missile barrage on the al-Asad airbase in Iraq, a defense official told Military Times.




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Judge Could Hold Up Trump Administration's Bid to Clear Flynn, Legal Experts say

The notoriously independent-minded federal judge who once said he was disgusted by the conduct of Michael Flynn could block the administration's bid to drop criminal charges against the former adviser to President Donald Trump, legal experts said.




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The DOJ's Lawless Reversal on Michael Flynn

Randall D. Eliason: The government's motion to dismiss the case against former national security adviser Michael Flynn is like nothing I've ever seen. It's a political screed dressed up as legal analysis, promoting the "deep state" conspiracy fantasies of President Trump. It epitomizes the politicization of the Justice Department under Attorney General William P. Barr. It is, in the truest sense of the word, lawless.




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Scientists Obtain 'lucky' Image of Jupiter

Astronomers have produced a remarkable new image of Jupiter, tracing the glowing regions of warmth that lurk beneath the gas giant's cloud tops. The picture was captured in infared by the Gemini North Telescope in Hawaii, and is one of the sharpest observations of the planet ever made from the ground.




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Jump into Fear with Jeremy Cowart

Jeremy Cowart was named the “Most Influential Photographers on the Internet” by Huffington Post in 2014. He’s the founder of a global photography movement, Help-Portrait, to give back to those in need. As well as many photography projects bridging empathy and creativity into awareness and action. If you’ve been a long time listener / watcher of this show, you’ll recognize Jeremy from one of the first episodes nearly 10 years ago. Jeremy’s vision and ambition have not slowed down. Today on the show, we get into his new book I’m Possible and his biggest project to date, building a hotel where every aspect serves someone in need. We get into facing fears, overcoming doubt, and how to turn the seemingly impossible to possible. In this episode: The fear of having a dream that’s so big. Chasing a dream for a decade or lifetime. How do you take action and get paralyzed because it’s so big? How to chase curiosity despite your fear of starting something new? Whether you’re just starting out or you’re thinking about transitioning from something you love doing and are already good at…. Battling against our inner monologue pulling us away from the thing we know we […]

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The Soulful Art of Persuasion with Jason Harris

As creators and entrepreneurs, getting our ideas out in the world is critical. And today, I have my long time friend Jason Harris in the hot seat to help us with just that. Jason is the founder and CEO of the award winning creative agency Mekanism. He is one of Creativity Mag’s most creative people in business, Top 100 People Who Make Advertising Great and about 52 other awards in the creative space. You’ve certainly seen his work if you’ve watched Superbowl commercials or heard of Peloton, Ben & Jerrys, HBO, and more. He also is one of the people that I look up to as a model of giving back. He donates a huge amount of his time to causes in which he believes and uses his marketing savvy for doing good in the world. I’m super inspired by our conversation today for so many reasons, but here’s handful to whet your palette: Of course we get into his new book The Soulful Art of Persuasion, in which Jason breaks down the art of sharing our ideas in an honest and authentic ways We talk about the ups and downs living life identifying as a professional creator, including the […]

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Harmony > Balance with Jason Calacanis

Today we’re going back to San Francisco with myself and Jason Calacanis on stage during my tour stop for my book Creative Calling. Jason is an investor and long time host of the This Week in Startups podcast. And, of course, Jason wastes no time in our conversation. He goes right to the heart of the matter by getting into failure, venture capitol, knowing when to quit, and when to push through. Enjoy! FOLLOW JASON: facebook | twitter | website Listen to the Podcast Subscribe   This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times.

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Self Reliance + Personal Uprising with John Jantsch

John Jantsch is a veteran marketer. He’s written several bestselling books including Duct Tape Marketing and The Referral Engine. He’s out with a new book called the Self-Reliant Entrepreneur: 366 Daily Meditations to Feed Your Soul and Grow Your Business  As you might know, I’m a bit of a fan of daily habits, so of course John gives us a little preview into some of the daily explorations of thoughts and writings from notable American authors. Of course, that’s not all…  we also get into: We go deep into following your own path and listening to your intuition. What we can learn from rabble rousers of our history and those who embraced counter culture to follow their own beliefs. The role that self-awareness has in pursuing our dreams. and much more. Enjoy! FOLLOW JOHN: facebook | twitter | website Listen to the Podcast Subscribe   This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New […]

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Choose Creativity – A Conversation with Jordon Harbinger

Recently sat down with my man Jordan Harbinger on his podcast The Jordan Harbinger Show. As a radio personality and a podcaster long before it was cool, Jordan is no stranger to the mic. It was a fun conversation and I hope you enjoy! A few of my fav topics: I share my framework for learning from the masters by deconstructing what they do and applying it My creative slumps and how I dug out How mindset matters and unwinding our self-limiting beliefs and much more … Big shoutout to Jordan for having me on the show … and if you haven’t already, be sure to check out his podcast The Jordan Harbinger Show anywhere you listen to podcasts. Enjoy! FOLLOW JORDAN: instagram| facebook | twitter | website Listen to the Podcast Subscribe   This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our […]

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Pay Attention to What Ignites You with Jody MacDonald

Imagine this: Your job is good, and safe, but it’s not fueling you anymore. You decide to quit your “real” job and sell all your belongings to live a life of adventure. And just as you are waving your last goodbye, the unthinkable happens and it changes everything. Like most of us, award winning photographer Jody MacDonald didn’t know what her path would be. Yet when her wake up call came, she listened. From train hopping in the Sahara to paragliding in the Himalaya, she’s no stranger to adventure and exploration. Her work blends insightful storytelling, big adventure expeditions and social change in the hopes of promoting the preservation of wild places. Men’s Journal named her “One of the 25 Most Adventures Women in the Past 25 Years and National Geographic said she’s one of the top female adventure photographers pushing the limits. I’ve admired Jody’s work from afar for years. Her life story and career arc is remarkable. It set her on a path to tackle some of the life’s biggest questions and what she has learned is pure gold. In this episode: Why waste your time on things that make you unhappy? What Jody does to tune into […]

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Create the Change You Seek with Jonah Berger

Jonah Berger is a marketing professor at the Wharton School at the University of Pennsylvania and internationally bestselling author of Contagious, Invisible Influence, and The Catalyst. Dr. Berger is a world-renowned expert on change, word of mouth, influence, consumer behavior, and how products, ideas, and behaviors catch on. He has published over 50 articles in top‐tier academic journals, teaches Wharton’s highest rated online course, and popular outlets like The New York Times and Harvard Business Review often cover his work. He’s keynoted hundred of events, and often consults for organizations like Google, Apple, Nike, and the Gates Foundation. Enjoy! FOLLOW JONAH: instagram | twitter | website Listen to the Podcast Subscribe   Watch the Episode This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times.

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Surviving + Thriving with Jasmine Star

If you missed my conversation with my dear friend photographer + entrepreneur Jasmine Star, we were LIVE on CreativeLive TV. CreativeLiveTV is a brand-new, free, 24/7 variety show, live-streamed from the very casual living rooms, studios, and kitchen tables of our worldwide community of legendary creators.  Worth checking out over at http://creativelive.com/tv. In this episode, we’re coming to you from our living rooms to chat about not just survive in these strange times, but to thrive. In particular, finding, participating, and growing your online community. Enjoy! FOLLOW JASMINE: instagram | twitter | website Listen to the Podcast Subscribe   Watch the Episode This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times.

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Do What You Can Do with Cellist Joshua Roman

Legendary musician Yo-Yo Ma called my guest today the future of classical music in America. Joshua Roman is a cellist, accomplished composer and curator whose performances embrace musical styles from Bach to Radiohead. At 22, he became the youngest principal cellist in the Seattle Symphony. Now as a soloist, his performances have been viewed by millions. I was able to catch up with Joshua on this special LIVE performance CreativeLive TV. Wherever you are in the world, hope this episode lifts you up. Please be sure to give Joshua a shout on the socials. Enjoy! FOLLOW JOSHUA: instagram | twitter | website Listen to the Podcast Subscribe   Watch the Episode This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times.

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Setting New Project Managers Up for Success

At Viget, we’ve brought on more than a few new Project Managers over the past couple of years, as we continue to grow. The awesome new people we’ve hired have ranged in their levels of experience, but some of them are earlier in their careers and need support from more experienced PMs to develop their skills and flourish.

We have different levels of training and support for new PMs. These broadly fall into four categories:

  • Onboarding: Learning about Viget tools and processes
  • Shadowing: Learning by watching others
  • Pairing: Learning by doing collaboratively
  • Leading: Learning by doing solo

Onboarding

In addition to conducting intro sessions to each discipline at Viget, new Viget PMs go through a lengthy set of training sessions that are specific to the PM lab. These include intros to:

PM tools and resourcesProject processes
Project typesProject checklists
Project taskingProject planning
Budgets, schedules, and resourcingRetrospectives
Working with remote teamsProject kickoffs
Thinking about developmentGithub and development workflow
Tickets, definition, and documentationQA testing
Account management

Shadowing

After PMs complete the onboarding process, they start shadowing other PMs’ projects to get exposure to the different types of projects we run (since the variety is large). We cater length and depth of shadowing based on how much experience a PM has coming in. We also try to expose PMs to multiple project managers, so they can see how PM style differs person-to-person.

We’ve found that it can be most effective to have PMs shadow activities that are more difficult to teach in theory, such as shadowing a PM having a difficult conversation with a client, or shadowing a front-end build-out demo to see how the PM positions the meeting and our process to the client. More straightforward tasks like setting up a Harvest project could be done via pairing, since it’s easy to get the hang of with a little guidance.

Pairing

While shadowing is certainly helpful, we try to get PMs into pairing mode pretty quickly, since we’ve found that most folks learn better by doing than by watching. Sometimes this might mean having a new PM setting up an invoice or budget sheet for a client while a more experienced PM sits next to them, talking them through the process. We’ve found that having a newer PM lead straightforward activities with guidance tends to be more effective than the newer PM merely watching the more experienced PM do that activity.

Another tactic we take is to have both PMs complete a task independently, and then meet and talk through their work, with the more experienced PM giving the less experienced PM feedback. That helps the newer PM think through a task on their own, and gain experience, but still have the chance to see how someone else would have approached the task and get meaningful feedback.

Leading

Once new PMs are ready to be in the driver’s seat, they are staffed as the lead on projects. The timing of when someone shifts into a lead role depends on how much prior experience that person has, as well as what types of projects are actively ready to be worked on.

Most early-career project managers have a behind-the-scenes project mentor (another PM) on at least their first couple projects, so they have a dedicated person to ask questions and get advice from who also has more detailed context than that person’s manager would. For example, mentors often shadow key client and internal meetings and have more frequent check-ins with mentees. This might be less necessary at a company where all the projects are fairly similar, but at Viget, our projects vary widely in scale and services provided, as well as client needs. Because of this, there’s no “one size fits all” process and we have a significant amount of customization per project, which can be daunting to new PMs who are still getting the hang of things.

For these mentorship pairings, we use a mentorship plan document (template here) to help the mentor and mentee work together to define goals, mentorship focuses, and touchpoints. Sometimes the mentee’s manager will take a first stab at filling out the plan, other times, the mentor will start that process.

Management Touchpoints

Along the way, we make sure new PMs have touchpoints with their managers to get the level of support they need to grow and succeed. Managers have regular 1:1s with PMs that are referred to as “project 1:1s”, and are used for the managee to talk through and get advice on challenges or questions related to the projects they’re working on—though really, they can be used for whatever topics are on the managee’s mind. PMs typically have 1:1s with managers daily the first week, two to three times per week after that for the first month or so, then scale down to once per week, and then scale down to bi-weekly after the first six months.

In addition to project 1:1s, we also have monthly 1:1s that are more bigger-picture and focused on goal-setting and progress, project feedback from that person’s peers, reflection on how satisfied and fulfilled they’re feeling in their role, and talking through project/industry interests which informs what projects we should advocate for them to be staffed on. We have a progress log template that we customize per PM to keep track of goals and progress.

We try to foster a supportive environment that encourages growth, feedback, and experiential learning, but also that lets folks have the autonomy to get in the driver’s seat as soon as they’re comfortable. Interested in learning more about what it’s like to work at Viget? Check out our open positions here.




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Freebie: 264 Vector Audio DJ Pack Icons

Icons packs are among the most desirable freebies around. There are several out there, going from a wide array of topics from user interfaces to personal finance. But sometimes you can find some rather unusual but clever additions to the icons universe. This Vector Audio DJ Pack is a nice example, brought to you exclusively …

Freebie: 264 Vector Audio DJ Pack Icons Read More »





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First impressions of the Fuji X-Pro2 (and the Fujinon 100-400mm lens)

Fuji released their new flagship camera this month, the X-Pro2. It is the first X-series camera to feature a 24MP sensor (compared to 16MP before) and it has a very interesting hybrid optical & electronic view finder. When I first […]




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Exploring Node.js Internals

Since the introduction of Node.js by Ryan Dahl at the European JSConf on 8 November 2009, it has seen wide usage across the tech industry. Companies such as Netflix, Uber, and LinkedIn give credibility to the claim that Node.js can withstand a high amount of traffic and concurrency. Armed with basic knowledge, beginner and intermediate developers of Node.js struggle with many things: “It’s just a runtime!” “It has event loops!




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Mirage JS Deep Dive: Understanding Mirage JS Models And Associations (Part 1)

Mirage JS is helping simplify modern front-end development by providing the ability for front-end engineers to craft applications without relying on an actual back-end service. In this article, I’ll be taking a framework-agnostic approach to show you Mirage JS models and associations. If you haven’t heard of Mirage JS, you can read my previous article in which I introduce it and also integrate it with the progressive framework Vue.js.




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Join Our New Online Workshops On CSS, Accessibility, Performance, And UX

It has been a month since we launched our first online workshop and, to be honest, we really didn’t know whether people would enjoy them — or if we would enjoy running them. It was an experiment, but one we are so glad we jumped into! I spoke about the experience of taking my workshop online on a recent episode of the Smashing podcast. As a speaker, I had expected it to feel very much like I was presenting into the empty air, with no immediate feedback and expressions to work from.




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DJI’s new Matrice 300 RTK drone offers a ridiculous 55-minutes of flight time and 2.7kg payload

DJI has announced their new Matrice 300 RTK “flying platform” (big drone) and the Zenmuse H20 hybrid camera series, to provide “a safer and smarter solution” to their enterprise customers. The M300 RTK, DJI says, is their first to integrate modern aviation features, advanced AI, 6-direction sensing and positioning, a UAV health management system and […]

The post DJI’s new Matrice 300 RTK drone offers a ridiculous 55-minutes of flight time and 2.7kg payload appeared first on DIY Photography.



  • DIY
  • dji
  • DJI M300 RTK
  • DJI Matrice 300 RTK
  • Matrice 300 RTK


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$L^p$-regularity of the Bergman projection on quotient domains. (arXiv:2004.02598v2 [math.CV] UPDATED)

We relate the $L^p$-mapping properties of the Bergman projections on two domains in $mathbb{C}^n$, one of which is the quotient of the other under the action of a finite group of biholomorphic automorphisms. We use this relation to deduce the sharp ranges of $L^p$-boundedness of the Bergman projection on certain $n$-dimensional model domains generalizing the Hartogs triangle.




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Integrability of moduli and regularity of Denjoy counterexamples. (arXiv:1908.06568v4 [math.DS] UPDATED)

We study the regularity of exceptional actions of groups by $C^{1,alpha}$ diffeomorphisms on the circle, i.e. ones which admit exceptional minimal sets, and whose elements have first derivatives that are continuous with concave modulus of continuity $alpha$. Let $G$ be a finitely generated group admitting a $C^{1,alpha}$ action $ ho$ with a free orbit on the circle, and such that the logarithms of derivatives of group elements are uniformly bounded at some point of the circle. We prove that if $G$ has spherical growth bounded by $c n^{d-1}$ and if the function $1/alpha^d$ is integrable near zero, then under some mild technical assumptions on $alpha$, there is a sequence of exceptional $C^{1,alpha}$ actions of $G$ which converge to $ ho$ in the $C^1$ topology. As a consequence for a single diffeomorphism, we obtain that if the function $1/alpha$ is integrable near zero, then there exists a $C^{1,alpha}$ exceptional diffeomorphism of the circle. This corollary accounts for all previously known moduli of continuity for derivatives of exceptional diffeomorphisms. We also obtain a partial converse to our main result. For finitely generated free abelian groups, the existence of an exceptional action, together with some natural hypotheses on the derivatives of group elements, puts integrability restrictions on the modulus $alpha$. These results are related to a long-standing question of D. McDuff concerning the length spectrum of exceptional $C^1$ diffeomorphisms of the circle.




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Grothendieck's inequalities for JB$^*$-triples: Proof of the Barton-Friedman conjecture. (arXiv:1903.08931v3 [math.OA] UPDATED)

We prove that, given a constant $K> 2$ and a bounded linear operator $T$ from a JB$^*$-triple $E$ into a complex Hilbert space $H$, there exists a norm-one functional $psiin E^*$ satisfying $$|T(x)| leq K , |T| , |x|_{psi},$$ for all $xin E$. Applying this result we show that, given $G > 8 (1+2sqrt{3})$ and a bounded bilinear form $V$ on the Cartesian product of two JB$^*$-triples $E$ and $B$, there exist norm-one functionals $varphiin E^{*}$ and $psiin B^{*}$ satisfying $$|V(x,y)| leq G |V| , |x|_{varphi} , |y|_{psi}$$ for all $(x,y)in E imes B$. These results prove a conjecture pursued during almost twenty years.




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Gabriel-Roiter measure, representation dimension and rejective chains. (arXiv:1903.05555v2 [math.RT] UPDATED)

The Gabriel-Roiter measure is used to give an alternative proof of the finiteness of the representation dimension for Artin algebras, a result established by Iyama in 2002. The concept of Gabriel-Roiter measure can be extended to abelian length categories and every such category has multiple Gabriel-Roiter measures. Using this notion, we prove the following broader statement: given any object $X$ and any Gabriel-Roiter measure $mu$ in an abelian length category $mathcal{A}$, there exists an object $X'$ which depends on $X$ and $mu$, such that $Gamma = operatorname{End}_{mathcal{A}}(X oplus X')$ has finite global dimension. Analogously to Iyama's original results, our construction yields quasihereditary rings and fits into the theory of rejective chains.




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On the Total Curvature and Betti Numbers of Complex Projective Manifolds. (arXiv:1807.11625v2 [math.DG] UPDATED)

We prove an inequality between the sum of the Betti numbers of a complex projective manifold and its total curvature, and we characterize the complex projective manifolds whose total curvature is minimal. These results extend the classical theorems of Chern and Lashof to complex projective space.




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Surjective endomorphisms of projective surfaces -- the existence of infinitely many dense orbits. (arXiv:2005.03628v1 [math.AG])

Let $f colon X o X$ be a surjective endomorphism of a normal projective surface. When $operatorname{deg} f geq 2$, applying an (iteration of) $f$-equivariant minimal model program (EMMP), we determine the geometric structure of $X$. Using this, we extend the second author's result to singular surfaces to the extent that either $X$ has an $f$-invariant non-constant rational function, or $f$ has infinitely many Zariski-dense forward orbits; this result is also extended to Adelic topology (which is finer than Zariski topology).




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A Hamilton-Jacobi Formulation for Time-Optimal Paths of Rectangular Nonholonomic Vehicles. (arXiv:2005.03623v1 [math.OC])

We address the problem of optimal path planning for a simple nonholonomic vehicle in the presence of obstacles. Most current approaches are either split hierarchically into global path planning and local collision avoidance, or neglect some of the ambient geometry by assuming the car is a point mass. We present a Hamilton-Jacobi formulation of the problem that resolves time-optimal paths and considers the geometry of the vehicle.




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Derivatives of normal Jacobi operator on real hypersurfaces in the complex quadric. (arXiv:2005.03483v1 [math.DG])

In cite{S 2017}, Suh gave a non-existence theorem for Hopf real hypersurfaces in the complex quadric with parallel normal Jacobi operator. Motivated by this result, in this paper, we introduce some generalized conditions named $mathcal C$-parallel or Reeb parallel normal Jacobi operators. By using such weaker parallelisms of normal Jacobi operator, first we can assert a non-existence theorem of Hopf real hypersurfaces with $mathcal C$-parallel normal Jacobi operator in the complex quadric $Q^{m}$, $m geq 3$. Next, we prove that a Hopf real hypersurface has Reeb parallel normal Jacobi operator if and only if it has an $mathfrak A$-isotropic singular normal vector field.




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Characteristic Points, Fundamental Cubic Form and Euler Characteristic of Projective Surfaces. (arXiv:2005.03481v1 [math.DG])

We define local indices for projective umbilics and godrons (also called cusps of Gauss) on generic smooth surfaces in projective 3-space. By means of these indices, we provide formulas that relate the algebraic numbers of those characteristic points on a surface (and on domains of the surface) with the Euler characteristic of that surface (resp. of those domains). These relations determine the possible coexistences of projective umbilics and godrons on the surface. Our study is based on a "fundamental cubic form" for which we provide a closed simple expression.




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Smooth non-projective equivariant completions of affine spaces. (arXiv:2005.03277v1 [math.AG])

In this paper we construct an equivariant embedding of the affine space $mathbb{A}^n$ with the translation group action into a complete non-projective algebraic variety $X$ for all $n geq 3$. The theory of toric varieties is used as the main tool for this construction. In the case of $n = 3$ we describe the orbit structure on the variety $X$.




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The conjecture of Erd"{o}s--Straus is true for every $nequiv 13 extrm{ mod }24$. (arXiv:2005.03273v1 [math.NT])

In this short note we give a proof of the famous conjecture of Erd"{o}s-Straus for the case $nequiv13 extrm{ mod } 24.$ The Erd"{o}s--Straus conjecture states that the equation $frac{4}{n}=frac{1}{x}+frac{1}{y}+frac{1}{z}$ has positive integer solutions $x,y,z$ for every $ngeq 2$. It is open for $nequiv 1 extrm{ mod } 12$. Indeed, in all of the other cases the solutions are always easy to find. We prove that the conjecture is true for every $nequiv 13 extrm{ mod } 24$. Therefore, to solve it completely, it remains to find solutions for every $nequiv 1 extrm{ mod } 24$.




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An Issue Raised in 1978 by a Then-Future Editor-in-Chief of the Journal "Order": Does the Endomorphism Poset of a Finite Connected Poset Tell Us That the Poset Is Connected?. (arXiv:2005.03255v1 [math.CO])

In 1978, Dwight Duffus---editor-in-chief of the journal "Order" from 2010 to 2018 and chair of the Mathematics Department at Emory University from 1991 to 2005---wrote that "it is not obvious that $P$ is connected and $P^P$ isomorphic to $Q^Q$ implies that $Q$ is connected," where $P$ and $Q$ are finite non-empty posets. We show that, indeed, under these hypotheses $Q$ is connected and $Pcong Q$.




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Multi-Resolution POMDP Planning for Multi-Object Search in 3D. (arXiv:2005.02878v2 [cs.RO] UPDATED)

Robots operating in household environments must find objects on shelves, under tables, and in cupboards. Previous work often formulate the object search problem as a POMDP (Partially Observable Markov Decision Process), yet constrain the search space in 2D. We propose a new approach that enables the robot to efficiently search for objects in 3D, taking occlusions into account. We model the problem as an object-oriented POMDP, where the robot receives a volumetric observation from a viewing frustum and must produce a policy to efficiently search for objects. To address the challenge of large state and observation spaces, we first propose a per-voxel observation model which drastically reduces the observation size necessary for planning. Then, we present a novel octree-based belief representation which captures beliefs at different resolutions and supports efficient exact belief update. Finally, we design an online multi-resolution planning algorithm that leverages the resolution layers in the octree structure as levels of abstractions to the original POMDP problem. Our evaluation in a simulated 3D domain shows that, as the problem scales, our approach significantly outperforms baselines without resolution hierarchy by 25%-35% in cumulative reward. We demonstrate the practicality of our approach on a torso-actuated mobile robot searching for objects in areas of a cluttered lab environment where objects appear on surfaces at different heights.




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Optimal Adjacent Vertex-Distinguishing Edge-Colorings of Circulant Graphs. (arXiv:2004.12822v2 [cs.DM] UPDATED)

A k-proper edge-coloring of a graph G is called adjacent vertex-distinguishing if any two adjacent vertices are distinguished by the set of colors appearing in the edges incident to each vertex. The smallest value k for which G admits such coloring is denoted by $chi$'a (G). We prove that $chi$'a (G) = 2R + 1 for most circulant graphs Cn([[1, R]]).




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Jealousy-freeness and other common properties in Fair Division of Mixed Manna. (arXiv:2004.11469v2 [cs.GT] UPDATED)

We consider a fair division setting where indivisible items are allocated to agents. Each agent in the setting has strictly negative, zero or strictly positive utility for each item. We, thus, make a distinction between items that are good for some agents and bad for other agents (i.e. mixed), good for everyone (i.e. goods) or bad for everyone (i.e. bads). For this model, we study axiomatic concepts of allocations such as jealousy-freeness up to one item, envy-freeness up to one item and Pareto-optimality. We obtain many new possibility and impossibility results in regard to combinations of these properties. We also investigate new computational tasks related to such combinations. Thus, we advance the state-of-the-art in fair division of mixed manna.




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On the regularity of De Bruijn multigrids. (arXiv:2004.10128v2 [cs.DM] UPDATED)

In this paper we prove that any odd multigrid with non-zero rational offsets is regular, which means that its dual is a rhombic tiling. To prove this result we use a result on trigonometric diophantine equations.




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Mathematical Formulae in Wikimedia Projects 2020. (arXiv:2003.09417v2 [cs.DL] UPDATED)

This poster summarizes our contributions to Wikimedia's processing pipeline for mathematical formulae. We describe how we have supported the transition from rendering formulae as course-grained PNG images in 2001 to providing modern semantically enriched language-independent MathML formulae in 2020. Additionally, we describe our plans to improve the accessibility and discoverability of mathematical knowledge in Wikimedia projects further.




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Recursed is not Recursive: A Jarring Result. (arXiv:2002.05131v2 [cs.AI] UPDATED)

Recursed is a 2D puzzle platform video game featuring treasure chests that, when jumped into, instantiate a room that can later be exited (similar to function calls), optionally generating a jar that returns back to that room (similar to continuations). We prove that Recursed is RE-complete and thus undecidable (not recursive) by a reduction from the Post Correspondence Problem. Our reduction is "practical": the reduction from PCP results in fully playable levels that abide by all constraints governing levels (including the 15x20 room size) designed for the main game. Our reduction is also "efficient": a Turing machine can be simulated by a Recursed level whose size is linear in the encoding size of the Turing machine and whose solution length is polynomial in the running time of the Turing machine.