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Erling D. Andersen

@primaldual.bsky.social
456 followers 313 following 104 posts

I spend most of my adult life on convex optimization and www.Mosek.com. In my spare time I like riding my racing bike and follow www.ob.dk. ORCID: orcid.org/0000-0001-6351-8761

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Reposted by Erling D. Andersen
Matteo Fischetti @matteofischetti.bsky.social · 26/09/2026
For all FP-riends #orms: Feasibility Pump + objective cutoff as a black box: what does it lose? On MIPLIB 2017 inside SCIP, a simple recovery beats SCIP's pump on 116 of 176 instances, loses on 9 (post hoc). Code and data: github.com/mfischetti-a... paper: www.researchgate.net/publication/...
github.com
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ArXiv math.OC Optimization and Control @optb0t.bsky.social · 17/09/2026
📚 New Arxiv Paper Title: Level-Set Geometry and the Theoretical Performance of PDHG for Conic Linear Optimization Authors: Zikai Xiong, Robert M. Freund Read more: arxiv.org/abs/2609.19097
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Erling D. Andersen @primaldual.bsky.social · 11/09/2026
I cannot help thinking that if 9/11 had not happened, then Trump would never have been president, and the world would be quite different today. Maybe the crazy people behind 9/11 achieved what they wanted in the end.
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tveskov @tveskov.com · 30/08/2026
Point/Counterpoint
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Erling D. Andersen @primaldual.bsky.social · 20/08/2026
Hundested havn
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Phillips OBrien @phillipspobrien.bsky.social · 18/08/2026
So North Korea helps Russia, Russia helps Iran, Iran fights the USA, and the USA now hates South Korea and loves North Korea. www.nbcnews.com/politics/nat...
nbcnews.com
Russia is shipping explosives to Iran to bolster its missile and drone arsenal in U.S. war
The Russian shipments, which haven’t been previously reported, underscore the deepening strategic alliance between Moscow and Tehran.
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The Northern Sun @thenorthernsun.bsky.social · 16/08/2026
The MSM completely missed the gravity of last night's Ukrainian missile strike on the Progress Rocket Center in Samara, Russia. This isn't just another industrial fire. This is the definitive end of independent Russian space dominance and a massive blow to their national pride. 1/5
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Ilyas Dogru @ilyasdogru.bsky.social · 10/08/2026
Har du også undret dig over, at du køber flere kWh, end bilen får? 🚗🔌 Det kaldes ladetab ⤵️ Vores tyske søsterorganisation ADAC har målt grundigt efter på fem biler: Lader man en Mercedes CLA 350 EQ fra en almindelig stikkontakt, er ladetabet på hele 24,2 %.
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Clément Canonne @ccanonne.github.io · 01/08/2026
"We're all worried," as what it means to do research (in my field, Theoretical CS) seems to be shifting, and shifting fast. What to do? Senior researchers must lead by example, knowing that not everything will pan out. What I'm suggesting below may not work everywhere, but here's my own advice: 1/
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Mark Hamill @markhamillofficial.bsky.social · 31/07/2026
See, it's funny because it's true. #Sad
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Erling D. Andersen @primaldual.bsky.social · 31/07/2026
I am blogging about the primal-dual simplex algorithm. erlingdandersen.blogspot.com/2026/07/the-... Maybe something for you @sophie.huiberts.me
erlingdandersen.blogspot.com
The parametric primal-dual simplex algorithm
In a recent Subject To podcast with Bob Vanderbei he mentions a primal-dual simplex algorithm. Bob also discusses the algorithm in his Line...
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Erling D. Andersen @primaldual.bsky.social · 26/07/2026
Now it is getting interesting.
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Erling D. Andersen @primaldual.bsky.social · 24/07/2026
Superligaen begynder en ny sæson i dag. Jeg er fuld af håb og lidt bekymret for OB.
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Erling D. Andersen @primaldual.bsky.social · 23/07/2026
Så sandt.
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Erling D. Andersen @primaldual.bsky.social · 06/07/2026
So the US national football team have gotten some Trump doping. I am truly surprised.
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The Atlantic @theatlantic.com · 18/06/2026
Iran got the United States to sign a document that even Americans described as degrading, mortifying, a total capitulation, Graeme Wood argues: “Watching Trump and his aides sell the deal is in some ways as humiliating as the deal itself.”
bit.ly
Iran Has Humiliated Trump
Officials in Tehran got the United States to sign a document that even Americans described as degrading, mortifying, a total capitulation.
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The Empty City @davidallengreen.bsky.social · 15/06/2026
Being on Bluesky is in itself a form of age verification.
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Erling D. Andersen @primaldual.bsky.social · 05/06/2026
Laura is discussing LP at SIOPT26.
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Erling D. Andersen @primaldual.bsky.social · 02/06/2026
Watching Karmarkar speaking at #SIOPT26
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Michael D. Green, PhD @michaeldgreen.phd · 28/05/2026
President of MIT not mincing words today in @statnews.com www.statnews.com/2026/05/27/s...
So let me say it as clearly as I can: Without basic scientific research, supported by the kind of farsighted public investment that allows large-scale, undirected, curiosity-driven inquiry, the scientific pipeline will run dry.
In daily life, people may not feel the effects right away, or even in 10 years. But we will feel it. And when someone we love needs therapies that could have emerged but didn't or when other countries now
investing in science can launch new science-based industries or run their societies on vast resources of fusion energy or reap the benefits of quantum computing power or advanced medical breakthroughs, America will wish it sustained its leadership in scientific research here and now.
Sally Kornbluth is the president of MIT.
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Phillips OBrien @phillipspobrien.bsky.social · 25/05/2026
Hi All, Just sent out this post. After all the talk about Trump's impending deal with Iran surfaced over the weekend, there really is only one question left. How badly has the USA lost this war? The possible answers are grim. open.substack.com/pub/phillips...
open.substack.com
There Is Only One Remaining Question--How Badly Has The USA Lost This War?
Hi All,
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Mick Ryan @warinthefuture.bsky.social · 17/05/2026
Ukraine launched 7,000 long-range drones in March: now, there is no more sanctuary in Russia. Meanwhile Trump told Xi he'd like Taiwan to "stay the way it is" and declined to commit to arms sales. My weekly update. mickryan.substack.com/p/russia-has...
mickryan.substack.com
Russia Has No Sanctuary Left. Ukraine's Deep Strike, the Beijing Summit and the Shape of a Contested Global Security Environment. The Big Five, 17 May 2026
My weekly update on war & competition. This week, Ukraine's continuing deep strikes, Russia's big hit on Kyiv, the Xi-Trump summit in Beijing and my Big 5 reading recommendations.
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anil oza @aniloza.bsky.social · 14/05/2026
wow — the preprint host, arxiv, is banning authors for a year if they submit papers with hallucinated citations 🤖
Twitter thread from Thomas Dietterich, reading "Attention 
@arxiv
 authors: Our Code of Conduct states that by signing your name as an author of a paper, each author takes full responsibility for all its contents, irrespective of how the contents were generated. 1/
3:03 PM · May 14, 2026
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Thomas G. Dietterich
@tdietterich
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1h
If generative AI tools generate inappropriate language, plagiarized content, biased content, errors, mistakes, incorrect references, or misleading content, and that output is included in scientific works, it is the responsibility of the author(s). 2/
Thomas G. Dietterich
@tdietterich
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1h
We have recently clarified our penalties for this. If a submission contains incontrovertible evidence that the authors did not check the results of LLM generation, this means we can't trust anything in the paper. 3/
Thomas G. Dietterich
@tdietterich
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1h
The penalty is a 1-year ban from arXiv followed by the requirement that subsequent arXiv submissions must first be accepted at a reputable peer-reviewed venue. 4/
Thomas G. Dietterich
@tdietterich
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1h
Examples of incontrovertible evidence: hallucinated references, meta-comments from the LLM ("here is a 200 word summary; would you like me to make any changes?"; "the data in this table is illustrative, fill it in with the real numbers from your experiments") end/"
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Erling D. Andersen @primaldual.bsky.social · 11/05/2026
Trump - Iran: 0 - 5 www.theatlantic.com/internationa...
theatlantic.com
Checkmate in Iran
Washington can’t reverse or control the consequences of losing this war.
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Timothy Snyder @timothysnyder.bsky.social · 09/05/2026
The U.S. has spent billions to lose a war that enriches its oligarchs, impoverishes the citizenry, sabotages its alliances, and strengthens its enemies. Empires have risen and failed before, but to my knowledge no state has ever chosen to kill its own power. snyder.substack.com/p/on-superpo...
snyder.substack.com
On Superpower Suicide
And the recovery of justice
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Anders Puck Nielsen @anderspucknielsen.dk · 04/05/2026
I see this view a lot, but we need to be mindful of the asymmetries. It would be a disaster for European countries to go to war with Iran, and it would require totally unrealistic amounts of aid to Ukraine to compensate for that. It's better for Europe to just focus on Ukraine themselves.
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Erling D. Andersen @primaldual.bsky.social · 22/04/2026
Go OB.
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Anton Gerashchenko @antongerashchenko.bsky.social · 22/04/2026
⚡️Ambassadors of EU member states have approved a €90 billion loan for Ukraine and a 20th sanctions package against Russia,Radio Liberty reports A formal written procedure has been launched,with completion expected tomorrow afternoon, a spokesperson for Council of the European Union presidency said.
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Anton Gerashchenko @antongerashchenko.bsky.social · 17/04/2026
Ukraine will become a key ally to Europe if Europe has to deter Russia on its own in case the US scales back or withdraws from NATO-Danish military expert Anders Puck Nielsen In his new video, @anderspucknielsen.dk explains that Ukraine becomes a key ally in this scenario⤵️ 📹:Anders Nielsen/YouTube
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Phillips OBrien @phillipspobrien.bsky.social · 12/04/2026
So US is going to blockade the Strait of Hormuz. No oil or anything else gets out. Prices will skyrocket. Nothing could be better from the Russian perspective. www.cnbc.com/2026/04/12/t...
cnbc.com
Trump says U.S. will blockade Strait of Hormuz after Iran peace talks fail
Trump said the U.S. blockade will stop Iran from policing the strait and benefiting economically while the rest of the world suffers from its closure.
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Erling D. Andersen @primaldual.bsky.social · 12/04/2026
substack.com/@wesodonnell...
substack.com
Wes O'Donnell (@wesodonnell)
Even in a trench, some things still feel human. A Ukrainian soldier grabs a few minutes of sleep with a cat curled into his chest, somewhere between exhaustion and duty. War strips away a lot. It als...
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Jon Cooper @joncooper-us.bsky.social · 12/04/2026
Oh, yeah, that was the Obama Iran deal.
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Erling D. Andersen @primaldual.bsky.social · 04/04/2026
U.S. allies haven’t forgotten about Trump’s tariffs, his threats against NATO, and his curtailing of aid to Ukraine—so he shouldn’t be surprised that they’re unwilling to help him in Iran, @anneapplebaum argues. www.theatlantic.com/ideas/2026/0...
theatlantic.com
Everyone but Trump Understands What He’s Done
Allied leaders know that any positive gesture they make will count for nothing.
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상일 (Sang-il) @sioum.bsky.social · 27/03/2026
4색 정리 새로운 증명이 arXiv에 올라왔습니다. New proof of the four color theorem by Yuta Inoue, Ken-ichi Kawarabayashi, Atsuyuki Miyashita, Bojan Mohar, Carsten Thomassen, Mikkel Thorup arxiv.org/abs/2603.24880
arxiv.org
The Four Color Theorem with Linearly Many Reducible Configurations and Near-Linear Time Coloring
We give a near-linear time 4-coloring algorithm for planar graphs, improving on the previous quadratic time algorithm by Robertson et al. from 1996. Such an algorithm cannot be achieved by the known p...
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Erling D. Andersen @primaldual.bsky.social · 02/04/2026
Another FIFA peace prize is waiting for him.
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Torben Quitzau @quitte.dk · 31/03/2026
Stolt sgu
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Quanta Magazine @quantamagazine.org · 26/03/2026
In the world of math, is it possible to take abstraction and rigor too far? The secret math society called Bourbaki, while enormously influential and important, might also serve as a cautionary tale. www.quantamagazine.org/in-math-rigo...
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Alli DeJong @allidejong.bsky.social · 22/03/2026
This is completely unbearable. But also like… why are his insane ramblings never summarized like this in the media? We gotta wait for a substack guy to put it together like this?
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Erling D. Andersen @primaldual.bsky.social · 22/03/2026
Så kan jeg roligt forsætte min morgen routine med at spise havregryn. Gerne grovvalsede og økologiske.
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Erling D. Andersen @primaldual.bsky.social · 22/03/2026
I charged my e car the other day from 30 to 80% for 3 euros thanks to cheap wind power. These days less dependency on oil is obvious.
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Rolf van der Hulst @rolfvanderhulst.bsky.social · 20/03/2026
Just learned that arXiv is becoming independent of Cornell. Statement by arXiv: tech.cornell.edu/arxiv/
tech.cornell.edu
Cornell Tech - arXiv
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Steve Flammia @sflammia.bsky.social · 13/03/2026
The arXiv is becoming a nonprofit separate from Cornell, and they're looking for a CEO. Please repost to let good candidates know! @dabacon.tachyon.institute, @harrowing.bsky.social, @michaelnielsen.bsky.social jobs.chronicle.com/job/37961678...
jobs.chronicle.com
Chief Executive Officer - New York City, New York (US) job with arXiv | 37961678
arXiv seeks its first CEO to champion open, free scientific discovery and guide the platform’s next chapter as an independent nonprofit.
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Erling D. Andersen @primaldual.bsky.social · 13/03/2026
Good US did not elect Kamala Harris, so we avoided the 3rd world war. Thanks US.
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Erling D. Andersen @primaldual.bsky.social · 12/03/2026
I wonder when Trump will get tired of ałl his winning.
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Thiago Serra @thserra.bsky.social · 12/03/2026
Thanks for all the OptiBeer @optimizer.bsky.social @jefflinderoth.bsky.social and for the OptiWine @lauraalbertphd.bsky.social Heading back to Corn Land from Dairy Land after a day packed with very interesting research discussions
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Ron Filipkowski @ronfilipkowski.bsky.social · 08/03/2026
A year ago we were supposed to be getting $2,000 rebate checks, DOGE was going to find $2 trillion in waste to balance the budget, we were going to pay no income taxes because tariffs would pay for everything, gas and home electric bills would be cut in half, and no new wars.
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Erling D. Andersen @primaldual.bsky.social · 06/03/2026
Time will not be nice to the Trump administration.
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Erling D. Andersen @primaldual.bsky.social · 28/02/2026
See you in Amsterdam summer 2027.
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ArXiv math.OC Optimization and Control @optb0t.bsky.social · 09/02/2026
📚 New Arxiv Paper Title: Circuit Diameter of Polyhedra is Strongly Polynomial Authors: Bento Natura Read more: arxiv.org/abs/2602.06958
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