What is the command for a struck out exists symbol
\exists gives you the flipped E, but what is the command for the negated symbol?
Solution 1:
The command for the negative existential quantifier is \nexists. However, I believe you should ask questions like this on the TeX site of Stack Exchange.
Solution 2:
This is a great site that lets you draw the symbol you want, and it shows a list of possible latex commands. \nexists was the first suggestion that popped up! http://detexify.kirelabs.org/classify.html