Let $x,y$ be two complex numbers. Then what the set of solutions of $x^y=xy$.

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One of my motivations for studying this problem is mathematical curiosity, as I am aware that it has the solution $2$. I am intrigued to determine whether 2 is the sole solution or if there are others.

The equation also exhibits an intriguing pattern:

...$=2$^^^$2=2$^^$2=2^2=2⋅2=2+2=1+1+1+1.$

In my opinion, this equation is worth solving.

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(Partial answer)

The whole set of solutions might be hard to determine in the present case. By inspection, we can find some of them, such as $x = y = 1$, $x = y = 2$ or $x = 0$ with $y > 0$ for instance. Provided suitable domains for $x$ and $y$, the Lambert W function permits to find a solution curve too, since your equation can be rewritten as $\frac{1}{x} = ye^{-y\ln x}$, hence $y = \frac{W\left(-\frac{\ln x}{x}\right)}{-\ln x}$.

Now, given that you are ultimately interested by the fact that $2+2 = 2\cdot2 = 2^2$, you may look at hyperoperations, because it is known that $H_n(2,2) = 4 \;\,\forall n \ge 1$ actually.