Logarithmically concave function
From Wikipedia, the free encyclopedia
A function 
is logarithmically concave (or log-concave for short), if its natural logarithm ln(f(x)), is concave. Note that we allow here concave functions to take value 
. Every concave function is log-concave, however the reverse does not necessarily hold (e.g., exp{ − x2}).
Examples of log-concave functions are the indicator functions of convex sets.
In parallel, a function is log-convex if its natural log is convex.
