Mathematician's Answer/Analysis

A Mathematician's Answer is technically correct yet pragmatically infelicitous.

"A, B, or C?" → "Yes"
Given a question presenting a set of options that are mutually exclusive yet collectively exhaustive, such as "Is it common or uncommon?", the answer implies only that the options are collectively exhaustive. It is infelicitous because the answerer knew that the asker knew that the options were collectively exhaustive. Because "None" is impossible, "Yes" gives no information. But in some cases, a "Yes" answer may imply cheekily "both" or "all of the above," that is, the unstated premise that they are mutually exclusive is false.