For linear maps `f : M → N` and injective `g : N → P`, the index of the range of `g ∘ f` is the product of the indices of the ranges of `f` and `g`.

Initializing...

For linear maps `f : M → N` and injective `g : N → P`, the index of the range of `g ∘ f` is the product of the indices of the ranges of `f` and `g`. · Prove2Me