Help understanding Replacement theorem Friedberg

Hello everyone, im having trouble understanding the Replacement Theorem proof outline in Friedberg Linear Algebra 4th pg 45.

Theorem 1.10 (Replacement Theorem)

Let be a vector space that is generated by a set containing exactly vectors, and let be a linearly independent subset of containing exactly vectors. Then and there exists a subset of containing exactly vectors such that generates

The proof is by induction on , I skipped the base case .

Inductive step

Let , be a linearly independent subset of consisting of vectors. Then is linearly independent, and so we may apply the induction hypothesis to conclude that and that theres is a subset of such that generates . Thus there exist scalars such that .

Note that , lest be a linear combination of which contradicts the assumption that L is linearly independent.

I am having trouble understanding why does .

Could someone give me a hint so I can understand. Thanks!

Edit: Is it beacause the induction hypothesis gives us and and since has an extra vector means that they cannot be equal?

Re: Help understanding Replacement theorem Friedberg

Since m <= n, the only choices are m < n and m = n. If m = n, then from

we have

i.e., L is not linearly independent, contrary to the assumption.

Re: Help understanding Replacement theorem Friedberg

Thanks, I over looked n-m=0