matthen

Genus-291 toroidal polyhedron

Model by Squilliams.

V=1770, E=6600, F=4250 (chi = -580, genus 291).

littledivy

The "-2 Jacobian" non-injective map — what a search turns up

Search query: Jacobian conjecture fake counterexample constant Jacobian -2 non-injective

The hit: Vitushkin's classic example

A map with Jacobian determinant exactly −2 that is not injective is a well-known "trick" example, usually attributed to Vitushkin:

Spacerat

#!/usr/bin/env python3
r"""
AN EXPLICIT DEGREE-3 JACOBIAN COUNTEREXAMPLE IN 11 VARIABLES
============================================================

Result
------

This file gives an explicit polynomial map

Andrewp2

Question:

There are many here who both believe that soon AI will be superhuman at maths, solving all Millenium problems and beyond, and yet also reject any claims that maths is 'dead', and believe that mathematics will thrive.

I'm curious, for those people, what is maths in that future?

Answer:

First of all, let me state that I'm not sure that I am one of those people who believe that mathematics will thrive in the near or far future, but this has been on my mind for some time and I figured I would get out my own thoughts on the issue.

jsmorph

GPT 5.4 compiled these instructions from this blog post by Scott Armstrong about his and Julia Kempe's Lean 4 formalization of De Giorgi–Nash–Moser theory.

Armstrong's recent math formalization notes (as interpreted)

This skill is for formalization projects in mature parts of

kim-em

ZEN Mathematics Center: New Project "LANA" Announcement

ZEN大学「ZMC（ZEN Mathematics Center; ZEN数学センター）」新プロジェクト「LANA」の発表

• Date: March 31, 2026
• Video: https://www.youtube.com/live/b9ZV-4T3iUo
• Duration: 1h 24m (first ~11 minutes are pre-stream holding screen)
• Language: Japanese (with some English from online participants, consecutively translated)

English Summary

Vilin97

#!/usr/bin/env python3
"""
Reconstruct the true PutnamBench SOTA timeline by combining:
1. Git commit history of results.json (for models added in real time)
2. Manual corrections for models whose paper/announcement dates differ
   from when they were added to the leaderboard.

Saves CSV and generates a plot.
"""

karpathy

"""
The most atomic way to train and run inference for a GPT in pure, dependency-free Python.
This file is the complete algorithm.
Everything else is just efficiency.

@karpathy
"""

import os       # os.path.exists
import math     # math.log, math.exp

FaffyWaffles

import Mathlib

open scoped BigOperators
open Filter
open scoped Nat

namespace Real

/-
============================================================

llllvvuu

import Mathlib

set_option linter.style.longLine false

open Set Filter Topology RealInnerProductSpace Gradient

variable {V : Type*} [NormedAddCommGroup V] [InnerProductSpace ℝ V] (f : V → ℝ) (X : ℝ → V) (r : ℝ)

def minimizers : Set V := {x | IsMinOn f Set.univ x}