Let \(T(m,n)\) denote the number of \(m \times n\) rectangular standard Young tableaux with the property that the difference of any two rows has all entries equal. Let \(T(n) = \sum\limits_{d|n} T(d,n/d)\). We find recurrence relations satisfied by the numbers \(T(m,n)\) and \(\hat{T}(n)\), compute their generating functions, and express them explicitly in some special cases.

A labeling (function) of a graph \(G\) is an assignment \(f\) of nonnegative integers to the vertices of \(G\). Such a labeling of \(G\) induces a labeling of \(L(G)\), the line graph of \(G\), by assigning to each edge \(uv\) of \(G\) the label \(\lvert f(u) – f(v)\rvert\). In this paper we investigate the iteration of such graph labelings.

In this thesis we examine the \(k\)-equitability of certain graphs. We prove the following: The path on \(n\) vertices, \(P_n\), is \(k\)-equitable for any natural number \(k\). The cycle on \(k\) vertices, \(C_n\), is \(k\)-equitable for any natural number \(k\), if and only if all of the following conditions hold:\(n \neq k\); if \(k \equiv 2, 3 \pmod{4}\) then \(n \neq k-1\);if \(k \equiv 2, 3 \pmod{4}\) then \(n \not\equiv k\pmod{2k}\) The only \(2\)-equitable complete graphs are \(K_1\), \(K_2\), and \(K_3\).
The complete graph on \(n\) vertices, \(K_n\), is not \(k\)-equitable for any natural number \(k\) for which \(3 \leq k < n\). If \(k \geq n\), then determining the \(k\)-equitability of \(K_n\) is equivalent to solving a well-known open combinatorial problem involving the notching of a metal bar.The star on \(n+1\) vertices, \(S_n\), is \(k\)-equitable for any natural number \(k\). The complete bipartite graph \(K_{2,n}\) is \(k\)-equitable for any natural number \(k\) if and only if \(n \equiv k-1 \pmod{k}\); or \(n \equiv 0, 1, \ldots, [ k/2 ] – 1 \pmod{k}\);or \(n = \lfloor k/2 \rfloor\) and \(k\) is odd.

The minimal number of triples required to represent all quintuples on an \(n\)-element set is determined for \(n \leq 13\) and all extremal constructions are found. In particular, we establish that there is a unique minimal system on 13 points, namely the 52 collinear triples of the projective plane of order 3.

A set \(T\) with a binary operation \(+\) is called an operation set and denoted as \((T, +)\). An operation set \((S, +)\) is called \(q\)-free if \(qx \notin S\) for all \(x \in S\). Let \(\psi_q(T)\) be the maximum possible cardinality of a \(q\)-free operation subset \((S, +)\) of \((T, +)\).

We obtain an algorithm for finding \(\psi_q({N}_n)\), \(\psi_q({Z}_n)\) and \(\psi_q(D_n)\), \(q \in {N}\), where \({N}_n = \{1, 2, \ldots, n\}\), \(( {Z}_n, +_n)\) is the group of integers under addition modulo \(n\) and \((D_n, +_n)\) is the dihedral group of order \(2n\).