English
The tangent cone of a product contains the tangent cone of each factor via coordinate projections.
Русский
Касательный конус произведения содержит касательные конуса каждого фактора через координатные проекции.
LaTeX
$$$\\operatorname{mapsTo\\_} t\\; (\\mathrm{tangentCone})$$$
Lean4
/-- If a subset of a real vector space contains a segment, then the direction of this
segment belongs to the tangent cone at its endpoints. -/
theorem mem_tangentConeAt_of_segment_subset {s : Set G} {x y : G} (h : segment ℝ x y ⊆ s) :
y - x ∈ tangentConeAt ℝ s x :=
mem_tangentConeAt_of_openSegment_subset ((openSegment_subset_segment ℝ x y).trans h)