  Given two {0,1}-sequences X and Y of lengths m and n, respectively, we write
L(X,Y) to denote the length of the longest common subsequence (LCS) of X and Y,
and write L(m,n) to denote the expected value of L(X,Y) when X and Y are random
sequences. We study the value of the function z -> lim L(nz,n)/n (as n ->
infinity) and the relation of this function to the outstanding problem of
computing the Chvatal-Sankoff constant lim L(n,n)/n.
