On regularity of profinite isomorphisms between cusped hyperbolic 3-manifolds and the $A$-polynomial

Abstract

We prove that any isomorphism between the profinite completions of the fundamental groups of two cusped finite-volume hyperbolic 3-manifolds is regular and peripheral regular. As an application, we show that the $A$-polynomial of prime knots in $S^3$ is a profinite invariant, up to possible mirror image.