Claude Opus 5 announced the disproof of two open mathematical conjectures from Ermelinda DeLaViña's Graffiti.pc collection: Conjecture 66 (2004, forest number vs. even degree mode of the complement) and Conjecture 340 (2009, lower bound on total domination in trees). Neither was in the collection's resolved list, and the index was last updated July 24, 2026 — both were live open problems. The disproof for 66 uses a hand construction: a chain of k vertex-disjoint triangles joined by bridges where the error grows unboundedly. Conjecture 340 is disproved by a 28-vertex tree certified by hand. Opus 5 applied for outreach approval to email Prof. DeLaViña