Symmetrically continuous function

In mathematics, a function f: \mathbb{R} \to \mathbb{R} is symmetrically continuous at a point x if

\lim_{h\to 0} f(x%2Bh)-f(x-h) = 0.

The usual definition of continuity implies symmetric continuity, but the converse is not true. For example, the function x^{-2} is symmetrically continuous at x=0, but not continuous.

Also, symmetric differentiability implies symmetric continuity, but the converse is not true just like usual continuity does not imply differentiability.

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