Ising n-fold integrals as diagonals of rational functions and integrality of series expansions: integrality versus modularity

A. Bostan, S. Boukraa, G. Christol +2

We show that the n-fold integrals ${\chi }^{(n)}$ of the magnetic susceptibility of the Ising model, as well as various other n-fold integrals of the "Ising class", or n-fold integrals f…