# Pseudoconvex function

$LaTeX: f$ is in $LaTeX: C^1$ and satisfies the property: $LaTeX: \textstyle \nabla f(x)(y-x) \ge 0$ implies $LaTeX: \textstyle f(y) \ge f(x).$ While every differentiable convex function is pseudoconvex, $LaTeX: \textstyle \arctan(x)$ is an example of a pseudoconvex function that is not convex.