# What is an integral with a circle through it?

1. Sep 13, 2009

### Luongo

$$\oint$$ what's the difference?

2. Sep 13, 2009

### slider142

This is a symbol usually used to denote a line integral over a closed curve (a curve homeomorphic to the circle, hence the circle symbol), but it can also be used for an integral over a closed manifold in more general circumstances.