4 problems

Let $M$ be an $n\times m$ $t$-disjunct matrix with constant column weight $b$. Set … and assume that $p$ is an integer. A Steiner system $\mathfrak{S}(n,b,p)$ is a family of $b$-su…

Let $C$ be an MDS code over a prime field $\mathbb{F}_p$, and let the Massey scheme be the secret-sharing scheme defined by $C$. A scheme is one-bit local leakage resilient if it r…

Let $\mathcal A$ be an access structure. It is ideal if it can be realized by an ideal entropic polymatroid, equivalently by an ideal distribution scheme. Let $\mathcal A^\bot$ den…

Let $P$ be a participant set, let $\mathcal A\subset 2^P$ be an access structure, and let $\mathcal A^\bot$ denote its dual access structure. Let $\sigma(\mathcal A)$ denote the en…