For a loop $a$ around $x$ and $\overline{a}$ its opposite, I want to construct an homotopy between $a \cdot \overline a$ and $c_x$. The usual solution is the one that can be found for example here.
However I was wondering if there is anything wrong with another one, namely $H(x,t)= \left\{\begin{array}{lr} a(2tx) & 0\leq x\leq 1/2\\ a(2t-2tx) & 1/2\leq x\leq 1\ \end{array} \right |?$
If no, then is there any benefit to using the usual one?