PROVE WITHOUT ANY POSSIBILITY OF REFUTATION the computational complexity $($worst case asymptotic lower bound$)$ and computational complexity class of the problem of determining, if there exists a bijective mapping between $2$ given trees, and design and PROVE WITHOUT ANY POSSIBILITY OF REFUTATION the computational complexity $($omega$)$ of an optimal algorithm solving that problem.$\backslash \backslash$

hint if the problem is undecidable then there is no possible solution.