Let $f:E\longrightarrow [-\infty,\infty]$ defined by
$$ f^*(y)=max_{x\in {E}}\{<y,x>-f(x)\}$$
is called the conjugate function of $f$. where $y\in{E^*}$ and $E,E^*$ are finite-dimensional real inner product vector spaces with inner product $<.,.>$ and norm $||.||$
Now, I want to know the relationship between the function and the conjugate function.
What is the relationship between the function diagram and the conjugate function diagram?