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Explicit moduli spaces for congruences of elliptic curves

We determine explicit birational models over Q for the modular surfaces parametrising pairs of N-congruent elliptic curves in all cases where this surface is an elliptic surface. In each case we also determine the rank of the Mordell-Weil lattice and the geometric Picard number.


Explicit moduli spaces for congruences of elliptic curves   (20 pages)     dvi   ps   ps.gz   pdf

There are two accompanying Magma files that check the calculations in the paper, available here and here.