English
There is a canonical additive character from AddCircle to Circle given by composing the additive-to-circle map with the natural projection.
Русский
Существуют канонический аддитивный символ из AddCircle в Circle, получаемый композицией соответствий.
LaTeX
$$$\\mathrm{toCircle\\_addChar} : AddChar(AddCircle(T), Circle)$ is canonical for all T.$$
Lean4
/-- The canonical map from the additive to the multiplicative circle, as an `AddChar`. -/
noncomputable def toCircle_addChar {T : ℝ} : AddChar (AddCircle T) Circle
where
toFun := toCircle
map_zero_eq_one' := toCircle_zero
map_add_eq_mul' := toCircle_add