lean2/tests/lean/assert_tac2.lean

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import data.nat
open nat algebra
example (a b c : nat) : a = 2 → b = 3 → a + b + c = c + 5 :=
begin
intro h1 h2,
have H : a + b = 2 + b, by rewrite h1,
have H : a + b = 2 + 3, by rewrite -h2; exact H,
have H : a + b = 5, from H,
rewrite H,
state,
rewrite add.comm
end