2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/130513This paper is concerned with the topological invariant of a graph given by the maximum degree of a Markov basis element for the corresponding graph model for binary contingency tables. We describe a degree four Markov basis for the model when the underlying graph is a cycle and generalize this result to the complete bipartite graph $K_{2,n}$. We also give a combinatorial classification of degree two and three Markov basis moves as well as a Buchberger-free algorithm to compute moves of arbitrary given degree. Finally, we compute the algebraic degree of the model when the underlying graph is a forest.24 pages, 1 figureCombinatoricsCommutative AlgebraStatistics Theorytext