English
If each f(i) is linearly independent with respect to id, and a certain finite-disjointness condition holds for all i and finite t, then the iUnion of f(i) is linearly independent.
Русский
Если каждый f(i) линейно независим и выполняется условие конечной раздельности, то iUnion f(i) линейно независим.
LaTeX
$$$\\text{linearIndepOn}_{i}\\; f(i) \\Rightarrow \\text{independence of union with finite disjointness}$$$
Lean4
@[simp]
theorem pair_add_smul_left_iff : LinearIndependent R ![x + b • y, y] ↔ LinearIndependent R ![x, y] :=
by
rcases subsingleton_or_nontrivial S with hS | hS; · simp [hS.elim b 0]
nontriviality R
simpa using pair_add_smul_add_smul_iff (x := x) (y := y) 1 b 0 1