That is called a schaefer(sic) stroke. If I could find my text book, I could give you the proper spelling :rolleyes:
Ah, found it. **Scheffer ** stroke
A quick summary of what everyone is saying…
|x| absoloute value of x
| can mean NAND
or
d|n = d divides n, ie. d|n = k, where k belongs to Z
or it can simply mean “such that”
Another vote for Bayes’ Theorem here. Yes, the | symbol can have many different meanings, but in this case I would say you are definately dealing with conditional probabilities in an expression of Bayes’ classic formula.