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For positive integers $ngeq kgeq t$, a collection $ mathcal{B} $ of $k$-subsets of an $n$-set $ X $ is called a $t$-packing if every $t$-subset of $ X $ appears in at most one set in $mathcal{B}$. In this paper, we give some upper and lower bounds for the maximum size of $3$-packings when $n$ is sufficiently larger than $k$. In one case, the upper and lower bounds are equal, in some cases, they differ by at most an additive constant depending only on $k$ and in one case they differ by a linear bound in $ n $.
By rectangle packing we mean putting a set of rectangles into an enclosing rectangle, without any overlapping. We begin with perfect rectangle packing problems, then prove two continuity properties for parallel rectangle packing problems, and discuss
Let $G$ be a graph of order $n(G)$ and vertex set $V(G)$. Given a set $Ssubseteq V(G)$, we define the external neighbourhood of $S$ as the set $N_e(S)$ of all vertices in $V(G)setminus S$ having at least one neighbour in $S$. The differential of $S$
We prove that there is $c>0$ such that for all sufficiently large $n$, if $T_1,dots,T_n$ are any trees such that $T_i$ has $i$ vertices and maximum degree at most $cn/log n$, then ${T_1,dots,T_n}$ packs into $K_n$. Our main result actually allows to
A linear system is a pair $(P,mathcal{L})$ where $mathcal{L}$ is a family of subsets on a ground finite set $P$, such that $|lcap l^prime|leq 1$, for every $l,l^prime in mathcal{L}$. The elements of $P$ and $mathcal{L}$ are called points and lines, r
Let $p_{k,3}(n)$ enumerate the number of 2-color partition triples of $n$ where one of the colors appears only in parts that are multiples of $k$. In this paper, we prove several infinite families of congruences modulo powers of 3 for $p_{k,3}(n)$ wi