Relative Obstructions and Spectral Diagnostics for Sheaves on Cell Complexes

Abstract

Let $\mathcal F$ be a finite-dimensional cellular sheaf on a finite simplicial complex $K$, and let $\epsilon:\mathcal F\to\mathcal W$ be a morphism to a constant reference sheaf. This paper studies a diagnostic use of the ordinary sheaf Laplacians together with the Laplacian of the mapping cone of the induced cochain map. A direct consequence of the standard mapping-cone sequence is that, when $K$ is connected, the degree-$0$ mapping-cone kernel is isomorphic to $\ker H^1(\epsilon)$. Thus this channel depends on the grounding morphism even when the intrinsic sheaf Laplacian is fixed. To complement these exact kernel statements, we use low-energy spectral subspaces and an integrated low-energy summary. These quantities are interpreted relative to the chosen inner products and numerical normalization; they are not asserted to define a metric distance between sheaves. Small examples illustrate three distinct readings of the resulting operators.