Koriolis: Not fully true. With 0 and 1 not(not x) = x in BM.
x is a variable, so I thought it was clear I was saying there is no equality (in the mathematical sense). So to make it clearer: both *expressions* are different. The fact that for 0 and 1 it works is a very minimum and is hardly relevant here.If x was of a true boolean type, both expression would be simply identical (Not Not x is then an identity, as you'd expect).