I am currently studying differential geometry. And I would like to know how one shows that two curves are not equivalent.
I know that two curves $c_1: I \rightarrow \mathbb{R^n}$ and $c_2: J \rightarrow \mathbb{R^n}$ are said to be equivalent if there exists function $\phi: I \rightarrow J$ s.t $c_2 = c_1 \circ \phi$
Now, In an exercice, I am asked to show that two curves are not equivalent. i.e: I am supposed to show that there doesn't exist $\phi$ s.t. $c_2 = c_1 \circ \phi$.
I don't know how to do that.