Theorem: BishopFin.count_true (Fifteen/Logic/BishopFin.lean)

State before:
α : Type u
β : Type v
inst✝³ : BishopFin α
inst✝² : BishopFin β
p q : α → Prop
inst✝¹ : DecidablePred p
inst✝ : DecidablePred q
⊢ (count fun x => True) = card α
Tactic:
dsimp [count]
State after:
α : Type u
β : Type v
inst✝³ : BishopFin α
inst✝² : BishopFin β
p q : α → Prop
inst✝¹ : DecidablePred p
inst✝ : DecidablePred q
⊢ List.countP (fun a => true) (elems α) = card α

State before:
α : Type u
β : Type v
inst✝³ : BishopFin α
inst✝² : BishopFin β
p q : α → Prop
inst✝¹ : DecidablePred p
inst✝ : DecidablePred q
⊢ List.countP (fun a => true) (elems α) = card α
Tactic:
rewrite [List.countP_true]
State after:
α : Type u
β : Type v
inst✝³ : BishopFin α
inst✝² : BishopFin β
p q : α → Prop
inst✝¹ : DecidablePred p
inst✝ : DecidablePred q
⊢ List.length (elems α) = card α

State before:
α : Type u
β : Type v
inst✝³ : BishopFin α
inst✝² : BishopFin β
p q : α → Prop
inst✝¹ : DecidablePred p
inst✝ : DecidablePred q
⊢ List.length (elems α) = card α
Tactic:
rfl
State after:
no goals