Theorem: IMOSL.IMO2012A5.Case2.GoodCase2.Rtwo_ne_zero (IMOSLLean4/IMO2012/A5/A5Cases/Case2.lean)

State before:
R : Type u_1
S : Type ?u.70700
inst✝² : Ring R
inst✝¹ : Ring S
inst✝ : NoZeroDivisors S
f : R → S
hf : GoodCase2 f
h : 2 = 0
⊢ f 2 = -1
Tactic:
rw [h, hf.map_zero]
State after:
no goals