Leader, Imre
Characterizing (aleph_0,aleph_1)-graphs ★★★
Call a graph an -graph if it has a bipartition so that every vertex in has degree and every vertex in has degree .
Problem Characterize the -graphs.
Keywords: binary tree; infinite graph; normal spanning tree; set theory
Few subsequence sums in Z_n x Z_n ★★
Conjecture For every , the sequence in consisting of copes of and copies of has the fewest number of distinct subsequence sums over all zero-free sequences from of length .
Keywords: subsequence sum; zero sum