For example if you have the operators A and B that both correspond to observables...If you asked in math you would have to 1) be able to appropriately tag your question under the relevant fields of math (who knows what they are) and 2) have to explain very well the background to where the math was coming from...
As long as you correctly state the question in terms of mathematical objects, mathematicians will understand and will immediately refer to the corresponding areas. In the case at hand I do not see any particular difficulty to address the theory of operators as suggested tag and I do not want to believe that you have to explain where the mathematics comes from; that those are observables in quantum mechanics or mere self-adjoint operators, it makes no difference (that is exactly the entire purpose of using the formalism in physics). For example, the below:
Question: let A, B be two self-adjoint operators such that [A,B] \subset i1 on their domains of definition. Prove that given any L^2 function on the circle then...
perfectly addresses any physics question related to the uncertainty principle and similars that can be asked on the mathematics platform. This said, I am nevertheless a strong supporter of keeping the mathematics questions on the physics area because:
- despite any personal opinion, mathematics does play a prominent role in modern physics, especially in QFT, string theory, quantum gravity and related areas. Most of nowadays research in the aforementioned is mainly carried exploiting mathematics rather than physical ideas (for instance I do not see any physics in the renormalisation procedures in QFT, to say one, but that could as well just be me...)
- physicists are, according to me, far better than mathematicians in the area of mathematical physics.
- (warning, very irrelevant!) those questions are the only ones I answer and understand ;-).