What can be said about topological properties of a space $X$ that is homeomorphic to $X\times X$ $?$

202 Views Asked by At

Given that $X$ is a topological space with infinite cardinality and $X$ is homeomorphic to $X\times X$.

  • (A)   $X$ cannot be connected.

  • (B)   $X$ cannot be compact.

  • (C)   $X$ cannot be homeomorphic to a subspace of $\mathbb R$.

  • (D)   None of the above.

If I take $\mathbb Q$ with discrete topology then $\mathbb Q$ satisfies the given condition while contradicting option (C).

Now for options (A) and (B), I know if $X$ is connected (compact) then $X\times X$ will be connected (compact).

But I cannot think of any examples of connected or compact spaces that are homeomorphic to their two-fold product.

Can anyone provide with some examples?