- #1
iamalexalright
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Homework Statement
Prove:
Let [tex]\tau \in L(V,W)[/tex], where dim(V) = dim(W) < infinity. Then [tex]\tau[/tex] is injective iff it is surjective.
Homework Equations
L(V,W) is the set of all linear transformations from V to W.
1. Any complement of ker(t) is isomorphic to im(t)
2. dim(ker(t)) + dim(im(t)) = dim(V)
The Attempt at a Solution
I'm pretty lost in starting this.
I know it is surjective iff im(t) = W
I know it is injective iff ker(t) = {0}
Should I assume its injective but not surjective (to move towards a contradiction)?
And maybe I don't understand the concept of an isomorphism but if:
[tex]im(\tau) = W[/tex] and
[tex]ker(\tau)^{c} \approx im(\tau)[/tex]
then how does the ker(t)^c relate to W?