mathlib3

7251bbf7 - feat(analysis/special_functions/trigonometric/angle): equality of twice angles (#14988)

feat(analysis/special_functions/trigonometric/angle): equality of twice angles (#14988) Add lemmas about equality of twice `real.angle` values (i.e. equality as angles modulo π). Co-authored-by: Eric Wieser <wieser.eric@gmail.com>