H. Derets

Algebraic Characterizations for Minors of Finite Graphs via Flow Transformation Monoid Division and Embedding

We prove three theorems on the flow monoids of finite graphs. First, we show that a non-empty finite graph G = (V, E) is connected if and only if its flow monoid contains a constant map on V, equivalently, if and only if it contains all constant maps on V. Second, we give a new characterization of graph minors in terms...