Suppose that r and n are non-negative integers satisfying r + n > 0. Denote the moduli stack over SpecZ of smooth elliptic curves with n marked points and r non-zero tangent vectors by M1,n+r⃗. Here the n marked points and the anchor points of the r tangent vectors are distinct. Taking each tangent vector to its anchor point defines a morphism M1,n+r⃗ → M1… (More)