Mirror Congruence for Rational Points on Calabi-Yau Varieties
  Wan conjectures that if $X$ and $Y$ form a strong mirror pair of Calabi-Yau varieties over a finite field $F_q$ with $q$ elements, then X and Y have the same number of $F_{q^k}$-rational points modulo $q^k$. We prove this conjecture under the condition that $Y$ can be obtained from $X$ through quotient construction. 
Lei Fu and Daqing Wan