2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153966Let X be a (connected and reduced) complex space. A q-collar of X is a bounded domain whose boundary is a union of a strongly q-pseudoconvex, a strongly q-pseudoncave and two flat (i.e. locally zero sets of pluriharmonic functions) hypersurfaces. Finiteness and vanishing cohomology theorems obtained in math/0503490 and math/0701549 for semi q-coronae are generalized in this context and lead to results on extension problem and removable sets for sections of coherent sheaves and analytic subsets.17 pages, 2 figuresComplex VariablesPrimary 32D15, 32D20 Secondary 32C25, 32F10text