Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 105 2 c Solution 2026-09-28
After integration by parts, the weak formulation isThe left side is the inner productwhich is positive definite and induces the usual norm. The right side is bounded in this norm. The Riesz representation theorem, equivalently the Lax-Milgram theorem, gives a unique weak solution. This is the weak Dirichlet problem for the massive Laplacian with mass one and the signs multiplied by .