Inverse problems for differential forms on Riemannian manifolds with boundary
Consider a real-analytic orientable connected complete Riemannian manifold $M$ with boundary of dimension $n≥ 2$ and let $k$ be an integer $1≤ k≤ n$. In the case when $M$ is compact of dimension $n≥ 3$, we show that the manifold and the metric on it can be reconstructed, up to an isometry, from the set of the Cauchy data for harmonic $k$-forms, given on an open subset of the boundary. This extends a result of  when $k=0$. In the two-dimensional case, the same conclusion is obtained when considering the set of the Cauchy data for harmonic $1$-forms. Under additional assumptions on the curvature of the manifold, we carry out the same program when $M$ is complete non-compact. In the case $n≥ 3$, this generalizes the results of  when $k=0$. In the two-dimensional case, we are able to reconstruct the manifold from the set of the Cauchy data for harmonic $1$-forms.