exact lt_tsub_of_add_lt_left card_person
Person Topic : Type
inst✝³ : Fintype Person
inst✝² : DecidableEq Person
inst✝¹ : Fintype Topic
inst✝ : DecidableEq Topic
card_person : 5 < Fintype.card Person
card_topic : Fintype.card Topic = 2
discusses : Person → Person → Topic
discussion_sym : ∀ (p1 p2 : Person), discusses p1 p2 = discusses p2 p1
p2 : Person
Person' : Type := { p3 // p3 ≠ p2 }
⊢ 4 < Fintype.card Person - 1
no goals