If the boundary $\partial M$of a manifold with boundary is connected,is $M$ connected?

78 Views Asked by At

Given a manifold with non-empty boundary $\partial M$, I am trying to see if the boundary is connected, will the manifold itself $M$be connected? I can not come up with any counter-example.

1

There are 1 best solutions below

0
On BEST ANSWER

Take the disjoint union of any manifold without boundary and a manifold with a connected boundary like a torus to which you remove a disc.