English
There exists a canonical section of the right projection S.rightHom, i.e., a right inverse to rightHom which is a group section.
Русский
Существуйте секция правого отображения, т.е. существует правый обратный к rightHom секции группы.
LaTeX
$$$ \\exists s: S.Section \\quad (S.rightHom) \\circ s = id_G $$$
Lean4
/-- An arbitrarily chosen section -/
@[to_additive surjInvRightHom /-- An arbitrarily chosen section -/
]
noncomputable def surjInvRightHom : S.Section
where
toFun := Function.surjInv S.rightHom_surjective
rightInverse_rightHom := Function.surjInv_eq S.rightHom_surjective