Ihara's lemma conjecture for Shimura-curve cohomology
Let qqq be a prime such that q∤NΔ′ℓ2q\nmid N\Delta'\ell^2q∤NΔ′ℓ2. Let T0ψ^(N){\bf T}_0^{\widehat\psi}(N)T0ψ(N) act on H1(X1(N),O)ψ^H^1({\bf X}_1(N),\mathcal O)^{\widehat\psi}H1(X1(N),O)ψ, and fix a maximal non-Eisenstein ideal…