Just saw I skipped over the f(0)=1 condition, so disregard that.

Surely not, since f(x) = 0 also satisfies f'(x) = f(x).

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...

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

Just learned that arXiv is becoming independent of Cornell. Statement by arXiv: tech.cornell.edu/arxiv/

I also show that the folding method can be applied to the continuous columns of mixed-integer linear programs, and in some cases can also be used to aggregate integer variables by detecting affine totally unimodular decompsitions, which describe a TU-like structure in the constraint matrix.

The new methods that I formulate extend the ``LP Folding'' reduction that aggregates permutation symmetries in linear programs to also aggregate reflection symmetries.

I am happy to share my latest work ``Folding Mixed-Integer Linear Programs and Reflection Symmetries'', where I formulate two new presolving techniques for handling symmetries in linear programs and mixed-integer linear programs.
Check out the preprint here:
lnkd.in/efgYeVSJ
lnkd.in/eGpim7U9

📢 #ISMP2027 comes to Amsterdam!

The 26th International Symposium on Mathematical Programming will be held July 25–30, 2027.

Join researchers from around the world to discuss advances, challenges, and opportunities in the theory and practice of mathematical optimization.

🔗 ismp2027.mathopt.nl
#MOS

I'm not sure about Gurobi, but for SCIP I suspect the natural dates formulation of the single machine scheduling problem with cuts based on release times could work:

pure.tue.nl/ws/portalfil...

Just access of any random memory location. This blog series explains it quite well:

www.ilikebigbits.com/2014_04_21_m...

I think the standard model of computation is partly to blame here. Especially O(1) memory access is not really realistic in practice and is closer to to O(sqrt(N)) in practice.

📚 New Arxiv Paper

Title: Circuit Diameter of Polyhedra is Strongly Polynomial
Authors: Bento Natura

Read more: https://arxiv.org/abs/2602.06958

Of course, most papers do define the variables and their meaning in the text above the model. But I think the latter ordering would still be easier to read if you just want to glance at the model.

The order 'objective - constraints - variables' that academic papers use to describe mathematical optimization problems is inconvenient, as it places the objective before you even know what the variables are. Wouldn't 'variables - constraints - objective' be a more natural progression?

130k Lines of Formal Topology in Two Weeks: Simple and Cheap Autoformalization for Everyone? This is a brief description of a project that has already autoformalized a large portion of the general topology from the Munkres textbook (which has in total 241 pages in 7 chapters and 39 sections)....

130k lines of formal topology in two weeks: Simple and cheap autoformalization for everyone? ~ Josef Urban. arxiv.org/abs/2601.032... #ITP #Mizar #LLMs #Math #Autoformalization

Given both your recent results, are you still motivated to investigate the simplex method further, or do you want to move on to new questions and topics?

The SCIP 10 optimization suite has many new interesting features and is fully open source. For binaries and downloads, check www.scipopt.org/index.php#do...

📚 New Arxiv Paper

Title: Geometry of the Reformulation-Linearization-Technique: Domination of Disjunctions
Authors: Hugo A. Hof, Matthias Walter

Read more: https://arxiv.org/abs/2511.13805

I shouldn't be surprised by this, but I just learned that Nvidia and AMD both disable FP64 performance units in their consumer cards so scientists and companies have to buy the high end ones at 5-10x the price. It's a valid business model but unfortunate for hobbyists like me who just want to try.

📚 New Arxiv Paper

Title: Linear Programming Hierarchies Collapse under Symmetry
Authors: Yuri Faenza, V\'ictor Verdugo, Jos\'e Verschae, Mat\'ias Villagra

Read more: https://arxiv.org/abs/2511.07766

Mostly deterministic RO with uncertainty sets (rather than distributionally RO), which can be formulated as some kind of Mixed Integer Program (does not need to be linear). Most interesting would be instances derived from real-world applications.

The only thing I could find is robust-optimization.com/instances/ , which collects instances from a few papers. Unfortunately, there seems to be no standardized data format for robust optimization problems.

Does there exist a commonly used public instance benchmark set for robust optimization? Or sets of instances which are frequently used within the literature?

This was hard work but now we are happy!

The #BOBILib paper has today been accepted for publication in Mathematical Programming Computation!

Here's the final version of the preprint: optimization-online.org/wp-content/u...!

And here's the website bobilib.org!

Spread the word and use it! :-)

🔄 Updated Arxiv Paper

Title: Implied Integrality in Mixed-Integer Optimization
Authors: Rolf van der Hulst, Matthias Walter

Read more: https://arxiv.org/abs/2504.07209

At least on Linux there seem to exist specialized fast timing functions: see stackoverflow.com/a/47003703 , which recommends to use 'clock_gettime()' and claims it only takes 3-5 nanoseconds on their system. I think it is likely that alternative calls exist in other operating systems.

What kind of crazy FPS are you running at where a syscall is too expensive? In my experience, most syscalls take on the order of 100 - 1000 cycles, which would take less than a microsecond on a modern cpu.

This is now out, we're super proud to have won the Land-Doig MIP competition prize for our algorithm for mixed-integer quadratic optimization!

passagemath-cmr passagemath: Combinatorial matrix recognition

passagemath 10.5.27 contains (a preliminary version of) the new package passagemath-cmr, an interface to the Combinatorial Matrix Recognition library by Matthias Walter et al., implementing Seymour's decomposition of TU matrices etc.
pypi.org/project/pass...
#Python #SageMath #OpenSource #MathSky

If you are checking out Cargo, I would also check out NPM (node package manager), which is one of the most popular javascript package managers.