This definition of $f$ says that for a given value of $x$ the value of $f$ is given by the smallest number among $|x|$,$1-|x|$ and $1/\alpha$ that is what $min$ means. Thus $f$ graph looks like a M. You can write a definition of $f$ piecewise. Then your integral is the sum of the areas of those two trapeses
This definition of $f$ says that for a given value of $x$ the value of $f$ is given by the smallest number among $|x|$,$1-|x|$ and $1/\alpha$ that is what $min$ means. Thus $f$ graph looks like a M. You can write a definition of $f$ piecewise. Then your integral is the sum of the areas of those two trapeses