Theorem: IMOSL.IMO2017A6.good_shift2 (IMOSLLean4/IMO2017/A6/A6.lean)

State before:
D : Type u_1
inst✝ : DivisionRing D
f : D → D
h : good f
h0 : f 0 = 1
x : D
⊢ f (x - 1) = f x + 1
Tactic:
rw [← good_shift h h0, sub_add_cancel]
State after:
no goals