A negated relation symbol indicating that two expressions are not similar or not asymptotically equivalent.
Examples
Stating that two expressions are not similar
f(x) = x^2 \nsim g(x) = x^3
Comparing non-similar triangles
\triangle ABC \nsim \triangle DEF
Stating non-similarity of probability distributions
P_1 \nsim P_2 \text{ (distributions are not similar)}