English
ChartAt on the product space equals the product of charts: chartAt (ModelProd H H') x = chartAt H x.fst .prod chartAt H' x.snd.
Русский
ChartAt на пространстве-образце равен произведению карт: chartAt (ModelProd H H') x = chartAt H x.fst .prod chartAt H' x.snd.
LaTeX
$$prodChartedSpace_chartAt$$
Lean4
/-- Same thing as `H × H'`. We introduce it for technical reasons,
see note [Manifold type tags]. -/
def ModelProd (H : Type*) (H' : Type*) :=
H × H'