This is very nice recognition of Hal Gabow! Hal spent his whole career as faculty at CU Boulder, and his legacy looms large for us. (Hal retired in 2008, and I unfortunately have never gotten a chance to meet him.)
Thanks! It was a PR (first time breaking 90 minutes!).
2026 Corvallis Half Marathon result.
I was lucky to get to run the Corvallis Half Marathon over the weekend in Oregon!
A couple of weeks ago, I was part of a theory Ph.D. thesis defense at U. Colorado where I enjoyed realizing that all of the other faculty on the committee were also runners (and that 3 of 4 are faster than I am).
Awesome! Yeah, I've had a lot of trouble not slowing down in the second half, even when starting at what I think is a conservative pace.
We need more details!
Photograph portrait of Martin Kreuzer. He is smiling, dressed formally with a bowtie, on a concrete walkway with metal railing, with a metallic-looking building in the background, and vibrant green trees in between.
Online CS Theory Seminar this Fri 2026-04-10!
We're excited to have Martin Kreuzer (Uni. Passau) presenting "From Code Equivalence to Polynomial Isomorphism"
www.digital.uni-passau.de/en/profiles/...
www.colorado.edu/cs-theory/th...
#MathSky #TCSSky #complexity #AlgebraicGeometry
Congratulations to fantastic @bouldertheory.bsky.social undergraduate @adithyacolorado.bsky.social! I've had the pleasure of getting to work with Adithya during his time at CU, and am very excited to hear about his work going forward.
Forget the h-index. The price of a name URL is the real measure of how successful a researcher is.
10 years ago today: my blog post on AlphaGo and Artificial Intelligence, which I wrote in grad school: hdbennett.wordpress.com/2016/03/18/a....
Wow.
Emphasis on the attack not coming close to the security claimed by Dilitihium. Dilithium claims 123, 186, and 265 bits of security for classical unforgeability; the attack gets running times of 202, 289, and 400 (for L2, L3, and L5, respectively).
(Ref: pq-crystals.org/dilithium/da..., Tbl 1.)
This New Yorker article about Claude (and AI in general) was excellent: www.newyorker.com/magazine/202.... In a world of 200-character hot takes, TNY's nuanced long-form journalism stands out even more. It's also funny: "investors ... including legendary League of Legends player Sam-Bankman-Fried."
That's fair. Yes, I think I'd still say "trained."
Students without technical knowledge will have no ability to recognize if AI outputs something that's sub-optimal or just plain wrong, let alone have any idea about how to produce the right thing. I also think that anthropomorphizing AI as having "read" books is rather misleading.
Students without technical knowledge will have no ability to recognize if AI outputs something that's sub-optimal or just plain wrong, let alone have any idea about how to produce the right thing. I also think that anthropomorphizing AI as having "read" books is rather misleading.
1/3 Fine-Grained Complexity Fest at DIMACS this July! Three back-to-back workshops on Algebraic Techniques, String Algorithms, and Graph Algorithms in fine-grained complexity, with a terrific speaker lineup. Organized by
@jalman.bsky.social , Elazar Goldenberg, and
@eigx.bsky.social.
10/10 meme choice.
The University of Colorado made a major, expensive "LLMification of higher ed" deal with OpenAI based on the recommendation of a committee (www.cu.edu/gen-ai#tabs-2) with no CS or STEM faculty, no faculty from CU Boulder, and no one with clear expertise in any aspect of AI or AI-based pedagogy.
From the combination of their nontrivial algorithm for co-3-SUM, they conclude that, assuming NSETH, there is no fine-grained reduction from k-SAT to 3-SUM (unlike, say, Orthogonal Vectors, for which such a reduction is known). 5/5
Their paper, which is the epitome of a good ITCS paper, also introduced the nondeterministic SETH (NSETH) assumption, which roughly asserts that there is no non-trivial algorithm for the co-k-SAT for large k (i.e., that certifying that formulas are UNSAT takes as long as solving the problem). 4/
But, it is not at all clear how to certify that there are *no* triples that sum to 0! Carmosino et al. give such an algorithm by noting that it's efficient to *count* 3-SUM solutions mod a small prime p using FFT, and by providing all "false positives mod p" as a witness. 3/
Recall that 3-SUM is the decision problem where the input is an array A = [a_1, ..., a_n] of integers and the goal is to decide whether there exist indices i, j, k s.t. a_i + a_j + a_k = 0. It is easy to certify YES instances very efficiently: the witness is just the indices of a 3-SUM triple. 2/
I wrote a short expository note about a beautiful result of Carmosino, Gao, Impagliazzo, Mihajlin,
Paturi, and Schneider for certifying NO instances of 3-SUM in roughly n^{3/2} time, beating the fastest known, roughly n^2-time deterministic algorithm: home.cs.colorado.edu/~hbennett/no.... 1/
I wrote up a little blog post proposing a slightly different way to write asymptotic notation. www.solipsistslog.com/a-simple-and...
In short, I think asymptotic notation should usually be written with an INequality. E.g., f(n) <= O(n^2), f(n) < o(log n), f(n) > 2^{-o(n)}, f(n) >= n^{-O(1)}, etc.
Otis Peak (12,486') and Hallett Peak (12,720') in Rocky Mountain National Park, Colorado. Spot the ptarmigan! 4/4
Mount Whitney (14,505'), the highest peak in California and the entire continental U.S. Roughly 6,300 feet of elevation gain and 20.75 miles. Done with @ilyaraz.bsky.social, who provided much-needed energy at the end. 3/4
Mount Adams (12,281'), the second-highest peak in Washington State and one of its five volcanoes. Roughly 6,800 feet of elevation gain and 12.25 miles. Yes, TSA allows ice axes in checked baggage. 2/4
To kick off 2026, here's a quick thread on a few mountain ascents from 2025, starting at home in Boulder, Colorado with Mount Sanitas (6,798') at night. 1/4
A deeply dangerous — and blatantly retaliatory action against Colorado — by the Trump administration.
NCAR is one of the most renowned scientific facilities in the WORLD — where scientists perform cutting-edge research everyday.
We will fight this reckless directive with every legal tool we have.