MathOverflow

Let $\mathcal{C}$ be a minimal quasi-category equivalent to the $\infty$-category of spaces.(Such a $\mathcal{C}$ is unique up to isomorphism of simplicial sets.)
In particular, equivalent objects of $C$ are equal, and homotopic morphisms are equal.
Can we "directly" interpret homotopy type theory in $\mathcal{C}$?...

I am trying to understand a variational argument appearing in a paper by R. Ferreira et. al (Critical exponents for a semilinear parabolicequation with variable reaction ) (Example 3.7), where the existence of a positive solution to$$\begin{cases}\Delta...

Let$$K:=L\left(2,\left(\frac{-3}{\cdot}\right)\right)=\sum_{k=1}^\infty\frac{(\frac k3)}{k^2}=\sum_{j=0}^\infty\left(\frac1{(3j+1)^2}-\frac1{(3j+2)^2}\right),$$ where $(\frac k3)$ is the Legendre symbol.Recently, I found the following (conjectural) curious...

As well-known, a Hadamard matrix is a square matrix with all coefficients $\pm 1$and pairwise orthogonal rows or columns. Such matrices exist conjecturally in every dimension divisible by $4$. Call a matrix with an odd number $n$ of columns an "almost...