i do understand wat it means...but of course i don't know the complete mathematics involved in it...correct me if my concept is wrong...it is a method used to cancel the infinities that come up in quantum field theories...on the other hand...how much i understand...electromagnetism is renormalizable becoz the quantum of light photon is a spin 1 particle...whereas graviton is a spin 2 particle...and so non-renormalizable...but y??