Okay I had a paper accepted with major revisions. In the original MS I use "!" to mean "not" - like, P(A|!B) to mean the probability of A given not B. We debated "¬" but my boss suggested it was too obscure.

... this reviewer wants me to change it to a superscript c, as in P(A|B^c) to mean the probability of A given the complement of B. It's FINE, just really jargony and this is intended to be for a public health audience and I'm grumpy.