I’ve been trying to negate an expression with a \not= symbol, using {{x=y}=undefined (or 0)}, but the Desmos grapher doesn’t quite getting. I’m searching for a way to inverse a piecewise expression, kind of like a not() function.
There’s no not() in the graphing calculator, so you have to be a little more creative to determine what is acceptable. If you don’t want x=y, then \abs(x-y)>0. It may be more helpful if you share a graph than a description.