I am not very well versed on set theory or syntax, but I thought I knew the basics.
However, in a book about databases I am reading now, the author uses "2^x" (where ^ is the exponent operator) to signify "a set of x."
For example, 2^dogs is a set of dogs. Etc. The author never really explained this or why he does it, I just picked up the meaning from context. I am not sure why the exponent operator is used, nor am I sure what the number 2 has to do with it. The sets being represented are NOT powers of 2 (in size)... they come in all sizes.
Is this a valid notation? I have not seen it anywhere before...