2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/152265We construct an oriented cobordism between moduli spaces of flat connections on the three holed sphere and disjoint unions of toric varieties, together with a closed two-form which restricts to the symplectic forms on the ends. As applications, we obtain formulas for mixed Pontrjagin numbers and Witten's formulas for symplectic volumes.33 pages, AMS-LaTeX, amssymb,eepic,epicDifferential Geometrytext