Ya. K. Shubin

collaborators

3 papers

math.CO2026

On the maximum number of vectors in ${0, \pm 1}^{n}$ with forbidden inner products

Ilya Lobatskii, Yakov Shubin

Let $M \subset {0, \pm 1}^{n}$ be a set such that $(m, m) = 4$ for every $m \in M$ , and $(m_{1}, m_{2}) \in {- 4, - 3, - 2, - 1, 0, 3}$ for any two distinct vectors $m_{1}, m_{2} \in M$ . We determine the ma…

math.CO2026

Short proofs of three combinatorial results in the Johnson scheme

Danila Cherkashin, Yakov Shubin

In this note, we give short proofs of three theorems concerning extremal problems in the Johnson scheme, or, in other terminology, on $(n, k, L)$ -systems. The main result is a proof…

math.CO2026

On supersaturation in the ErdÅs--SÃ³s problem

Andrey Kupavskii, Yakov Shubin

The following classical question in extremal set theory is due to Erd\H os and SÃ³s: what is the size of the largest family $F \subset (k [ n ])$ with no two sets $F_1…

On the maximum number of vectors in {0,±1}n with forbidden inner products

Short proofs of three combinatorial results in the Johnson scheme

On supersaturation in the ErdÅs--SÃ³s problem

On the maximum number of vectors in ${0, \pm 1}^{n}$ with forbidden inner products

On supersaturation in the ErdÅs--SÃ³s problem