English
A variant of the previous endpoint intersection when s ≠ t under linear independence assumptions.
Русский
Вариант пересечения концов при s ≠ t при предположениях линейной независимости.
LaTeX
$$$$ [c+x -[\mathbb{K}] c+x t y] \cap [c+x -[\mathbb{K}] c+x s y] = \{ c+x \}. $$$$
Lean4
theorem midpoint_mem_segment [Invertible (2 : 𝕜)] (x y : E) : midpoint 𝕜 x y ∈ [x -[𝕜] y] :=
by
rw [segment_eq_image_lineMap]
exact ⟨⅟2, ⟨invOf_nonneg.mpr zero_le_two, invOf_le_one one_le_two⟩, rfl⟩