theorem
proved
tactic proof
card_weight_zero_three
show as:
view Lean formalization →
formal statement (Lean)
191theorem card_weight_zero_three :
192 (Finset.univ.filter (fun v : F2Power 3 => hammingWeight v = 0)).card = 1 := by
proof body
Tactic-mode proof.
193 have hsubset :
194 (Finset.univ.filter (fun v : F2Power 3 => hammingWeight v = 0)) = {0} := by
195 ext v
196 simp [Finset.mem_filter, Finset.mem_univ, Finset.mem_singleton, weight_zero_iff]
197 rw [hsubset]
198 rfl
199
200/-- The three weight-1 vectors of `F2Power 3` are
201 `(true, false, false)`, `(false, true, false)`,
202 `(false, false, true)`. -/