Theorem: Pos.lt_of_add_lt_add_left (Extra/Pos/Lemmas.lean)

State before:
x y z : Pos
⊢ z + x < z + y → x < y
Tactic:
by_toNat
State after:
x y z : Pos
⊢ z.toNat + y.toNat > z.toNat + x.toNat → y.toNat > x.toNat

State before:
x y z : Pos
⊢ z.toNat + y.toNat > z.toNat + x.toNat → y.toNat > x.toNat
Tactic:
exact Nat.lt_of_add_lt_add_left
State after:
no goals