|Date||Apr 15, 2022|
Suppose that O_L is the ring of integers of a number field L, and suppose that f(z) is a normalized Hecke eigenform for Γ0(N)+. We say that f is non-ordinary at p if there is a prime ideal p ⊂ OL above p for which a_f(p) ≡ 0 (mod p). In authors’ previous paper it was proved that there are infinitely many Hecke eigenforms for SL2(Z) such that are non-ordinary at any given finite set of primes. In this talk, we extend this result to some genus 0 subgroups of SL2(R), namely, the normalizers Γ0(N)+ of the congruence subgroups Γ0(N). This is joint with Wenjun Ma.