Contractible as an Unbased Space but Not Contractible as a Based Space

81 Views Asked by At

An unbased space $X$ is contractible if $id_X$ is homotopic to a constant function, that is, any function which carries all of $X$ to single point.

Is there an unbased contractible space $X$ such that for any base point $x_0\in X$, $X$ is not contractible as a based space ?