My sigh was in reference to his entire comment to my simple request for proof of claim. There was no challenge, just a reasonable request.
Sorry, I should have made it more clear that I was referring to the request for proof of the claim for the “BTW, she never wrote anything else” part.
There is no proving that negative. If you only meant proof of the Truman Capote wrote TKAM claim, I don’t think that is something that will ever be proven beyond a shadow of a doubt one way or the other. But if we’re talking proof that “BTW, she never wrote anything else”, there is no proving it.