\nmid
The symbol \nmid is used in mathematics to denote that one number does not divide another. It is the negation of the divisibility relation, which is represented by the symbol | (mid).
Indicates that 'a' does not divide 'b'.
a \nmid b
The number 5 does not divide 12.
5 \nmid 12
The expression n^2 + 1 does not divide n^3 - n.
n^2 + 1 \nmid n^3 - n