The parity dimension of a graph \( G \) is defined as the dimension of the null space of its closed neighborhood matrix \( N \). A graph with parity dimension \( 0 \) is called all parity realizable (APR). In this paper, a simple recursive procedure for calculating the parity dimension of a tree is given, which is more apt to be used in the context of enumeration than the graph-theoretical characterizations due to Amin, Slater, and Zhang. Applying the recursive relation, we find asymptotic formulas for the number of APR trees and for the average parity dimension of a tree.

The Ramsey multiplicity \( M(G) \) of a graph \( G \) is defined to be the smallest number of monochromatic copies of \( G \) in any two-coloring of edges of \( K_{R(G)} \), where \( R(G) \) is the smallest integer \( n \) such that every graph on \( n \) vertices either contains \( G \) or its complement contains \( G \). With the help of computer algorithms, we obtain the exact values of Ramsey multiplicities for most of isolate-free graphs on five vertices, and establish upper bounds for a few others.