On an Archimedean analogue of Tateʹs conjecture Original Research Article

We consider an Archimedean analogue of Tateʹs conjecture, and verify the conjecture in the examples of isospectral Riemann surfaces constructed by Vignéras and Sunada. We prove a simple lemma in group theory which lies at the heart of T. Sunadaʹs theorem about isospectral manifolds.