13 lines
353 B
Text
13 lines
353 B
Text
import data.int
|
|
open int
|
|
|
|
theorem abs_thm1 (a b : int) : a - b = a + -b :=
|
|
by rewrite ↑sub -- unfold sub
|
|
|
|
theorem abs_thm2 (a b : int) : a - b = a + -b :=
|
|
by rewrite ^sub -- unfold sub
|
|
|
|
definition double (x : int) := x + x
|
|
|
|
theorem double_zero (x : int) : double (0 + x) = (1 + 1)*x :=
|
|
by rewrite ⟨↑double, zero_add, mul.right_distrib, one_mul⟩
|