I would be rather surprised if it hasn't been proven to lose. Since you're so keen on proving everything, where is your proof that it hasn't been proven to lose? Do you have one? If not, why are you criticising others?
i dont have a proof of math standard that there isnt a proof out there (in fact, such a feat would be impossible), but I am proposing a lack of knowledge, which is falsifiable. I will happily admit being wrong if you can find one, but you have to find one first.

I would be rather surprised if it hasn't been proven to lose. Since you're so keen on proving everything, where is your proof that it hasn't been proven to lose? Do you have one? If not, why are you criticising others?