Double negation bug

[scottmangiapane]

Double negation results in an error message saying that the input is invalid.

Ex:
    AvB works
    (AvB) works
    (~(AvB)) doesn't work

[mrieppel]

Thanks! But that's just the syntax I'm using for propositional logic. The grammar is:

p ::= Atomic | ~p | (p & p) | (p v p) | (p > p) | (p <> p)

Negation doesn't introduce parentheses, so the double negation of (AvB) would be ~~(AvB), just like the double negation of P would be ~~P, rather than ((P)).

[scottmangiapane]

Oh okay, I see what you mean. My original though process was that (A NAND
B) NAND C could only be written as ((A&B)&C) (and therefore cause the
parenthesis problem), because I didn't know that Sheffer stroke was the
same thing as NAND and I can just use that instead.

Also, great website! I particularly like the conversion to LaTeX table.

[mrieppel]

Cool, happy to hear you like the program! The double-NAND formula you have ((A&B)&C) is well formed as it stands. It would only be ill-formed if you didn't have the second conjunct, as in ((A&B)).