theorem
Hex.GraphIso.Nauty.VSet.countP_le_of_imp
{α : Type u_1}
{p q : α → Bool}
{l : List α}
:
(∀ (x : α), x ∈ l → p x = true → q x = true) → List.countP p l ≤ List.countP q l
countP is monotone under pointwise implication of the predicate
on the list's elements.
theorem
Hex.GraphIso.Nauty.VSet.filter_eq_of_imp_of_length_eq
{α : Type u_1}
{p q : α → Bool}
{l : List α}
(himp : ∀ (x : α), x ∈ l → p x = true → q x = true)
(hlen : (List.filter p l).length = (List.filter q l).length)
:
Two filters ordered by pointwise implication are equal when they
have the same length.
theorem
Hex.GraphIso.Nauty.VSet.countBelow_erase_of_mem
{n : Nat}
{s : VSet n}
{v : Nat}
(h : s.mem v = true)
(k : Nat)
:
v < k → (s.erase v).countBelow k + 1 = s.countBelow k