I'm beginning a new unit in class on probability sets but I don't know what the U and upside down U symbols mean.

Answer 1

I think U is union but I'm not sure about the upside down U.

Answer 2

D = {x E U l is a doctor } M = {x E U l is a male} (the administrator, nurses, and women also have the same notation as above.I also know it is not E but I don't have that symbol) But for D (upside down U) complement of M would I describe it as enployees who aren't male but are doctors