English
The same bound for finrank holds in the vector-span context when inserting p into an affine subspace s.
Русский
Та же граница по размерности справедлива векторному Span при добавлении p в аффинное подпространство s.
LaTeX
$$finrank_k(vectorSpan_k(insert p ((s: Set P)))) ≤ finrank_k((direction_affineSpan k s)) + 1$$
Lean4
/-- Adding a point to a set with a finite-dimensional span increases the dimension by at most
one. -/
theorem finrank_vectorSpan_insert_le_set (s : Set P) (p : P) :
finrank k (vectorSpan k (insert p s)) ≤ finrank k (vectorSpan k s) + 1 :=
by
rw [← direction_affineSpan, ← affineSpan_insert_affineSpan, direction_affineSpan]
refine (finrank_vectorSpan_insert_le _ _).trans (add_le_add_right ?_ _)
rw [direction_affineSpan]