On the page 32 of Lee's book Manifolds and differential geometry, he writes:
In the definition of path connectedness..., we used continuous paths, but it is not hard to show that if two points on a smooth manifold can be connected by a continuous path, then they can be connected by a smooth path.
I do not quite understand.
First of all, what does a path being smooth mean? A path on a manifold is a function: $ p:[0,1]\rightarrow M $
I think to be continuous is in the topological sense.
But what does smooth mean? Is it in the diffeomorphic sense?
Do we regard $[0,1]$ as a set in the manifold $\mathbb{R}$ and applying the definition of smoothness of function between manifolds?
After all, I wonder how to prove this statement.