# Injection on QxQ

aaaa202

For the set {a^2+b^2 , a,b $\in$ Q}. Am i then right in saying that the map:

f(a^2+b^2)=(lal,lbl) is an injection on QxQ (the absolute values are there to make sure f is well-defined)? And is this how you write a thing like this formally.

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