English
The auxiliary groups for different coordinates i and j coincide as groups on the homotopy quotient.
Русский
Группы-ассистенты по разным координатам i и j совпадают как группы на factoring of Homotopy.
LaTeX
$$$(\\mathrm{auxGroup}\\ i) = (\\mathrm{auxGroup}\n j)$ as groups$$
Lean4
/-- Group structure on `HomotopyGroup` obtained by pulling back path composition along the
`i`th direction. The group structures for two different `i j : N` distribute over each
other, and therefore are equal by the Eckmann-Hilton argument. -/
abbrev auxGroup (i : N) : Group (HomotopyGroup N X x) :=
(homotopyGroupEquivFundamentalGroup i).group