Paper 2, Section II, F
Part II, 2017
Let be a non-constant elliptic function with respect to a lattice . Let be a fundamental parallelogram whose boundary contains no zeros or poles of . Show that the number of zeros of in is the same as the number of poles of in , both counted with multiplicities.
Suppose additionally that is even. Show that there exists a rational function such that , where is the Weierstrass -function.
Suppose is a non-constant elliptic function with respect to a lattice , and is a meromorphic antiderivative of , so that . Is it necessarily true that is an elliptic function? Justify your answer.
[You may use standard properties of the Weierstrass -function throughout.]