For a value , let = (the limit from the left) and = (the limit from the right).[more]
If = = , the function is continuous at .
If = ≠ , the function has a removable discontinuity at .
If ≠ , and both values are finite, the function has a jump discontinuity at .
If ≠ , and one or both values is infinite, the function has an infinite discontinuity at . This is also called an essential discontinuity.[less]