- #1
Syrus
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Homework Statement
I'm reading from the first edition of Axler's Linear algebra done right. In the section on sums of vector subspaces, he states:
U = {(x,0,0) ∈ F3 | x ∈ F}
W = {(y,y,0) ∈ F3 | y ∈ F}
and
1.7 U + W = {(x,y,0) ∈ F3 | x,y ∈ F}
However, shouldn't the answer be U + W = {(x+y,y,0) ∈ F3 | x,y ∈ F}? You could write z = x+y, but it seems incorrect to reuse x (instead of z) as a substitute variable in such a case- if this is at all what he's doing.