Hall's theorem for hypergraphs

Infinite, highly connected digraphs with no two arc-disjoint spanning trees

Acyclic systems of representatives and acyclic colorings of digraphs

Jordan Graphs

Fractional Kernels in Digraphs

LP duality in infinite hypergraphs

Menger's theorem for countable graphs

On the strength of König's duality theorem for infinite bipartite graphs

Minimal non-two-colorable hypergraphs and minimal unsatisfiable formulas

On k-transversals

How to guess two letters correctly

Counting 1-factors in infinite graphs

An interior points algorithm for the convex feasibility problem

Coloring by two-way independent sets

Independence—domination duality

The Max-Flow Min-Cut theorem for countable networks

The number of edges in critical strongly connected graphs

Fourier transform imitations

On a theorem of lovász on covers inr-partite hypergraphs

Fractional matchings and covers in infinite hypergraphs