I was reading a nice paper by Seiberg on 5d susy gauge theories. Just in the introduction I stumbled upon something I had never thought about: "**The spinor representation of SO(4,1) is four dimensional and is pseudoreal. Since the vector of SO(4,1) is in the antisymmetric product of two spinors, the miniml SUSY algebra is generated by two charges**." This is is from hep-th/9608111.

My question goes as following: How can we determine such stuff? How can I know if the spinor representation of SO(something) is something dimensional? How can I find out about the isomorphisms between various Lie groups important for QFTs? Is there a list which physicists use? Is there a general reference where we can consult on such issues for any space-time dimension and any QFT? If not would it not be useful to have one?

Maybe a vague question but being in the beginning of my grad studies this is a very relevant question for people like me. Any help would be of great appreciation.