Hello,
I have to proof that when R and S are equivalence relations then $\displaystyle R \cup S$ is an equivalence relation if and only if $\displaystyle R \cup S=RS$.
Hello,
I have to proof that when R and S are equivalence relations then $\displaystyle R \cup S$ is an equivalence relation if and only if $\displaystyle R \cup S=RS$.
Can anyone give me a hint?
You need to expand a bit on notation.
I assume that $\displaystyle R~\&~S$ have the same domain.
But the notation $\displaystyle RS$ is not standard. How is it defined?