theorem
proved
term proof
nine_is_D_sq
show as:
view Lean formalization →
formal statement (Lean)
85theorem nine_is_D_sq : (9 : ℕ) = 3^2 := by decide
proof body
Term-mode proof.
86
87/-! ## Information-theoretic content. -/
88
89/-- The full cross-pattern matrix has 25 entries (5×5 patterns). The
90 non-trivial off-diagonal entries (excluding J=0 row/col which is null)
91 are 4×4 = 16. -/