Theorem: simple_proof (HausdorffSchool/Session1_Basics/Tutorial.lean)

State before:
G : Type
inst✝¹ : Group G
g h : G
R : Type
inst✝ : CommRing R
a b : R
p q r : Prop
h1 : p → q
h2 : q → r
⊢ p → r
Tactic:
sorry
State after:
no goals