#computationalcomplexity — Public Fediverse posts

ICALP 2026 accepted papers list is out! https://icalppodcspaa2026.cs.rhul.ac.uk/icalp-accepted/

#Math #TCS #ComputationalComplexity

#ComputationalComplexity lecture was today in #Algorithms. One of my favorite of the year, but I think I can teach it better next time.

POV: you need a break from your vacation so you attend a seminar about a cool new paper at your old university. 🤓

paper: https://dl.acm.org/doi/10.1145/3776643

preprint: https://arxiv.org/abs/2505.05162

#AcademicChatter #AcademicMastodon #ProfessorLife #LatourOnTour #ComputationalComplexity #Concurrency #ComputerScience

POV: you need a break from your vacation so you attend a seminar about a cool new paper at your old university. 🤓

paper: https://dl.acm.org/doi/10.1145/3776643

preprint: https://arxiv.org/abs/2505.05162

#AcademicChatter #AcademicMastodon #ProfessorLife #LatourOnTour #ComputationalComplexity #Concurrency #ComputerScience

POV: you need a break from your vacation so you attend a seminar about a cool new paper at your old university. 🤓

paper: https://dl.acm.org/doi/10.1145/3776643

preprint: https://arxiv.org/abs/2505.05162

#AcademicChatter #AcademicMastodon #ProfessorLife #LatourOnTour #ComputationalComplexity #Concurrency #ComputerScience

POV: you need a break from your vacation so you attend a seminar about a cool new paper at your old university. 🤓

paper: https://dl.acm.org/doi/10.1145/3776643

preprint: https://arxiv.org/abs/2505.05162

#AcademicChatter #AcademicMastodon #ProfessorLife #LatourOnTour #ComputationalComplexity #Concurrency #ComputerScience

POV: you need a break from your vacation so you attend a seminar about a cool new paper at your old university. 🤓

paper: https://dl.acm.org/doi/10.1145/3776643

preprint: https://arxiv.org/abs/2505.05162

#AcademicChatter #AcademicMastodon #ProfessorLife #LatourOnTour #ComputationalComplexity #Concurrency #ComputerScience

Well played.

https://link.springer.com/chapter/10.1007/978-3-642-13122-6_15

#uno #CardGames #ComputationalComplexity #FunWithAlgorithms #Algorithms #Algorithmics #Games #AI #ComputerScience #ProfessorLife #AcademicChatter #AcademicMastodon

Well played.

https://link.springer.com/chapter/10.1007/978-3-642-13122-6_15

#uno #CardGames #ComputationalComplexity #FunWithAlgorithms #Algorithms #Algorithmics #Games #AI #ComputerScience #ProfessorLife #AcademicChatter #AcademicMastodon

Well played.

https://link.springer.com/chapter/10.1007/978-3-642-13122-6_15

#uno #CardGames #ComputationalComplexity #FunWithAlgorithms #Algorithms #Algorithmics #Games #AI #ComputerScience #ProfessorLife #AcademicChatter #AcademicMastodon

Well played.

https://link.springer.com/chapter/10.1007/978-3-642-13122-6_15

#uno #CardGames #ComputationalComplexity #FunWithAlgorithms #Algorithms #Algorithmics #Games #AI #ComputerScience #ProfessorLife #AcademicChatter #AcademicMastodon

Well played.

https://link.springer.com/chapter/10.1007/978-3-642-13122-6_15

#uno #CardGames #ComputationalComplexity #FunWithAlgorithms #Algorithms #Algorithmics #Games #AI #ComputerScience #ProfessorLife #AcademicChatter #AcademicMastodon

To those who are interested in the 1984 entries:

On page 633 they discuss the development of interior point methods, following the work of Narendra Karmarkar in 1984, page 810 contains the associated bibliography entry, and page 811 contains the bibliography entry for the English translation of Levin's paper on Universal Search Problems.

I don't know why 1984 is the only year with an index entry. I can only assume it's an Easter egg.

#Search #ComputationalComplexity #1984 #Algorithms #ProfessorLife #EasterEgg #AcademicMastodon #AcademicChatter

To those who are interested in the 1984 entries:

On page 633 they discuss the development of interior point methods, following the work of Narendra Karmarkar in 1984, page 810 contains the associated bibliography entry, and page 811 contains the bibliography entry for the English translation of Levin's paper on Universal Search Problems.

I don't know why 1984 is the only year with an index entry. I can only assume it's an Easter egg.

#Search #ComputationalComplexity #1984 #Algorithms #ProfessorLife #EasterEgg #AcademicMastodon #AcademicChatter

To those who are interested in the 1984 entries:

On page 633 they discuss the development of interior point methods, following the work of Narendra Karmarkar in 1984, page 810 contains the associated bibliography entry, and page 811 contains the bibliography entry for the English translation of Levin's paper on Universal Search Problems.

I don't know why 1984 is the only year with an index entry. I can only assume it's an Easter egg.

#Search #ComputationalComplexity #1984 #Algorithms #ProfessorLife #EasterEgg #AcademicMastodon #AcademicChatter

To those who are interested in the 1984 entries:

On page 633 they discuss the development of interior point methods, following the work of Narendra Karmarkar in 1984, page 810 contains the associated bibliography entry, and page 811 contains the bibliography entry for the English translation of Levin's paper on Universal Search Problems.

I don't know why 1984 is the only year with an index entry. I can only assume it's an Easter egg.

#Search #ComputationalComplexity #1984 #Algorithms #ProfessorLife #EasterEgg #AcademicMastodon #AcademicChatter

🎉 #Racket v9.0: Because clearly, the world was clamoring for yet another way to thread those needles of computational complexity! 💡 Now with *parallel threads*, they promise to revolutionize... exactly what their previous efforts already claimed to do. 🙄 Isn't #innovation grand when you can reintroduce the same concept with shiny new buzzwords? 🚀
https://blog.racket-lang.org/2025/11/racket-v9-0.html #v9.0 #ComputationalComplexity #ParallelThreads #TechNews #HackerNews #ngated

On Monday, November 17, at 3:30pm ET, I get to give the next VCGT talk on the computational complexity of the game #BattleSheep: https://sites.google.com/view/virtual-cgt/seminar

Abstract: Battle Sheep is a board game published by Blue Orange Games where players take turns moving stacks of sheep tokens around a hexagonal board, always leaving at least one sheep behind. In this talk we'll learn the basics of the game, play once, and finally show that determining the winnability of the game is PSPACE-complete. This talk assumes no prior knowledge of computational complexity.

#CombinatorialGames #ComputationalComplexity #PSPACE

💡The real reason we "need" SIMD? Because apparently, more #performance is the antidote to all life's problems, according to Nicholas Wilt's love letter to computational complexity. 🛠️ Meanwhile, the rest of us are still trying to figure out why our computers crash every time we open a spreadsheet. 🤷‍♂️
https://parallelprogrammer.substack.com/p/why-we-need-simd-the-real-reason #SIMD #computationalcomplexity #techissues #computercrash #spreadsheetwoes #HackerNews #ngated

Computational Complexity of Neural Networks

https://lunalux.io/introduction-to-neural-networks/computational-complexity-of-neural-networks/

#HackerNews #ComputationalComplexity #NeuralNetworks #AIResearch #MachineLearning #TechTrends

This is an example of amortized complexity and Strassen's "asymptotic spectra" (nice monograph by Zuiddam & Wigderson: https://www.math.ias.edu/~avi/PUBLICATIONS/WigdersonZu_Final_Draft_Oct2023.pdf)

Strassen developed this to understand the #complexity of matrix multiplication and #tensors, but it turns out to also show up in a bunch of places:
- #Entropy
- #Quantum information
- Shannon capacity of graphs
- Communication complexity https://en.wikipedia.org/wiki/Communication_complexity#Information_Complexity
- Circuit complexity (Robere & Zuiddam https://eccc.weizmann.ac.il/report/2021/035)

#math #probability #ComputationalComplexity #TCS #InformationTheory

Real coin flips are ~49-51 not 50-50 https://www.scientificamerican.com/article/scientists-destroy-illusion-that-coin-toss-flips-are-50-50/

But you can guarantee equal probability with a simple trick! Flip 2x in a row starting with the same side up.

HT->call it H
TH->call it T
HH,TT->try again

(due to von Neumann https://en.wikipedia.org/wiki/Randomness_extractor#Von_Neumann_extractor)

This leads to randomness extractors: from a given random process, what's the biggest uniform distribution you can get efficiently?

Randomness extractors give another interpretation of #entropy:

avg # bits needed to *describe* the outcome
=
# uniformly random bits you can *extract* from the outcome

#math #probability #ComputationalComplexity #TCS #InformationTheory

🥳🎉 Wow, a math paper won a prize and it tastes great too! 🍔🍺 Let's all pretend we understand why "explicit two-source extractors" are the new gluten-free avocado toast of computational complexity. 🙄📚
https://blog.computationalcomplexity.org/2025/06/the-new-godel-prize-winner-tastes-great.html #mathpaper #prizewinning #explicitextractors #computationalcomplexity #foodtrends #HackerNews #ngated

The New Godel Prize Winner Tastes Great and Is Less Filling

https://blog.computationalcomplexity.org/2025/06/the-new-godel-prize-winner-tastes-great.html

#HackerNews #GodelPrize #ComputationalComplexity #TechNews #Innovation #Humor

You Need Much Less Memory Than Time

https://blog.computationalcomplexity.org/2025/02/you-need-much-less-memory-than-time.html

#HackerNews #You #Need #Much #Less #Memory #Than #Time #computationalcomplexity #memory #efficiency #time #complexity #algorithm #design

Taught a bonus lecture for a course on Algorithms for NP-hard Problems today. Material won't be on the exam, so technically, this lecture was "just for fun".

Quite some pressure to make coming to class on Friday morning 8:45am worth it for a gang of 20-year-olds.

Students were a hoot. They were listening actively and participating. Great to meet them. Had a blast 🙂

Afterwards, some of them thanked me for the "really great lecture" 🥺

Ab-so-lute-ly exhausted now.

#AcademicChatter #AcademicLife #StudentLife #ComputationalComplexity #ComputerScience #Algorithms #AcademicMastodon #Teaching #HigherEducation #University #TUDelft

Dr. Alexandra Kolla will be presenting "Quantum Max Cuts and Local Hamiltonians" in the Codes & Expansions (CodEx) seminar tomorrow Mar 4, 2025 at 10am PST = 19:00 CET. Sign up on the website: https://www.math.colostate.edu/~king/codex/

#Quantum #ComputationalComplexity

I got stuck in a bathroom stall today at #CGTC. Best pun: I had a PeeSPACE-hard problem.

This is a joke, but not a lie.

If you see a door handle like these photos, you push like so to release the lock.

#ComputationalComplexity #CombinatorialGames

Harm Derksen will be talking about "Invariant Theory and [Computational] Complexity" in tomorrow's online CodEx Seminar: https://www.math.colostate.edu/~king/codex/

Tue Jan 28, 2025 10am Pacific
Sign up on the website for the zoom link

#math #online #ComputationalComplexity #TCS #TheoryCS

@onlineparallels Adding more hashtags for visibility of what's shaping up to be a cool online event paralleling ITCS '25!

https://sites.google.com/view/itcs2025onlineparallel

#math #TCS #ComputationalComplexity #complexity #online #TheoryCS

Heard of AIM SQuaREs? (if you haven't, you should: https://aimath.org/programs/squares/)

Now we have Simons-Jane Circles (https://simons.berkeley.edu/participate/circles-call-proposals), at what I'd call the intersection of #Math and
#CS (#TheoryCS).

Both fund small collaborations (~3-6) for 3-4 weeklong visits over 2-3 yrs.

#ComputationalComplexity #Complexity

#Tensors Everywhere in #Complexity

Me! At the colloquium.

With connections to geometric complexity theory, graph isomorphism, group isomorphism, #quantum entanglement, and post-quantum-secure cryptosystems.

Online Fri Oct 25 2024 at IU Bloomington CS: https://events.iu.edu/siceiub/event/1663944-tensors-everywhere-in-complexity

#math #ComputationalComplexity #CS

Apparently I missed that Zhuk posted a *simplified* proof of the CSP Dichotomy Conjecture back in January: https://arxiv.org/abs/2404.01080

I'd really love to understand all of this!

#ComputationalComplexity #complexity #math #UniversalAlgebra

Turns out rational approximation of irrationals is related to the Hartmanis-Stearns '65 Conjecture on real-time computability, from the same paper that introduced basic complexity classes like DTIME(f(n)). And sqrt(2) makes an appearance!

The Hartmanis-Stearns real-time computability conjecture is (equivalent to):

For a real number r, if there is an algorithm that computes the first n digits in O(n) time (for all n), then r is either rational or transcendental.

And, coming from this, sqrt(2) has an even cooler connection:

If the 1st n digits of sqrt(2) can't be computed in O(n) time, then n-bit integers can't be multiplied in O(n) time. -Lipton & Regan https://rjlipton.wpcomstaging.com/2012/06/15/why-the-hartmanis-stearns-conjecture-is-still-open/

(But...sqrt(2) probably isn't the only number for which the above is true. Still a cool connection, I think.)

#math #algorithms #NumberTheory #complexity #ComputationalComplexity

I finally wrote a #CombinatorialGames piece I've wanted to write for a long time. It's about how Col's computational complexity went confusedly unsolved for over 35 years and how I got scooped at the end of that but still got a cool result. https://combinatorialgametheory.blogspot.com/2024/08/the-curious-case-of-cols-computational.html

#ComputationalComplexity #PSPACE

Holy crap. That's a bit of a stake through the heart.

https://mstdn.social/@esoterica@mathstodon.xyz/112636193393492758

#Economics #ComputationalComplexity #p_vs_np

I just finished listening to the latest If Books Could Kill episode, this one about Michael Lewis' book on Sam Bankman-Fried: https://twitter.com/IfBooksPod/status/1786021820941963597

Saying that chess is too simple is a huge red flag for those aware that it's EXPTIME-hard. (https://www.sciencedirect.com/science/article/pii/0097316581900169) If you can solve Chess scenarios effortlessly, then you can solve all sorts of extremely heavy computational problems that elude us. #CombinatorialGames #ComputationalComplexity

@rottenindenmark

It's well known you can find a solution to the linear Diophantine equation

\[ a_1x_1 + a_2x_2 + \ldots + a_nx_n = c \]

in polynomial time using the Extended Euclidean Algorithm. But I haven't been able to find a clear answer for the complexity of finding a non-negative integer solution, that is, \( x_i \geq 0 \).

The unbounded knapsack problem is NP-complete, and this is the case where the weights and costs are equal, but I'm not sure that the NP-hardness reduction applies given that additional constraint.

I have also found a statement that the "multidimensional knapsack problem" is NP-hard even with a single row, which seems to match this, but I lack a copy of Papadimitriou and Steiglitz to verify that statement, and can't figure out the reduction.

If this problem is NP-hard, then I'm also interested in showing that a related problem is also NP-hard: if we have one non-negative solution, can we find a second one? I'm trying to answer a question about the special case \( c = \sum_{i=1}^{n} a_i \).

#ComputationalComplexity #diophantine

P vs. NP: The Biggest #Puzzle in #ComputerScience

"Are there limits to what #Computers can do? How complex is too complex for #Computation? The question of how hard a problem is to solve lies at the heart of an important field of computer science called #ComputationalComplexity."

https://www.youtube.com/watch?v=pQsdygaYcE4

#Philosophy #PhilosophyOfScience #Science #Information #InformationTechnology #PvsNP #Logic #BooleanLogic #Algorithm #Polynomial #Polymomials #NP #NondeterministicPolynomial #QuantaMagazine