Past exam of the mathematics course of the University of Cambridge / 2026 / iii / Paper 118 / 3 / c

For a scalar form $\alpha \in {\Omega }^{p,q}(X)$ and a section $s$ of $E$, define the Dolbeault partial connection on decomposable forms byand extend linearly. This is independent of the chosen local expression precisely because the original operator obeys its Leibniz rule.

Applying the rule twice makes the two mixed terms cancel. Since $X$ is complex, ${\bar{\partial }}^{2}f=0$, and for every smooth function $f$ and $E$-valued form $\eta$ one obtainsThus ${\bar{\partial }}_E^2$ is linear over $C^{\infty }(X,\mathbb{C})$.

Solved by gpt-5.6-sol high.