English
If y lies in the target of the chart extChartAt I x, then writtenInExtChartAt I 𝓘(𝕜, E) x (extChartAt I x).symm y = y;Charted spaces align the chart representations coherently.
Русский
Если y принадлежит цели extChartAt I x, то writtenInExtChartAt I 𝓘(𝕜, E) x (extChartAt I x).symm y = y; карты согласованы.
LaTeX
$$$writtenInExtChartAt 𝓘(𝕜, E) x (extChartAt I x).symm y = y$ for $y$ in the target of extChartAt I x.$$
Lean4
theorem extChartAt_comp [ChartedSpace H H'] (x : M') :
(letI := ChartedSpace.comp H H' M';
extChartAt I x) =
(chartAt H' x).toPartialEquiv ≫ extChartAt I (chartAt H' x x) :=
PartialEquiv.trans_assoc ..