This question came about when I was using LaTeX, funny enough. I noticed that the following equivalence in syntax when typing the Hamiltonian operator:
\hat{mathcal{H}}
\mathcal{\hat{H}}
Both yield the same resulting character, $\mathcal{\hat{H}}$.
Noticing that these two "functions," \hat and \mathcal, are interchangeable, I couldn't help but notice a similarity with math.
Is there anything in mathematics in which two functions are interchangeable in this manner?
