We decided that “trivial” means “proved.” So we joked with the mathematicians: “We have a new theorem - that mathematicians can prove only trivial theorems, because every theorem that’s proved is trivial.” The mathematicians didn't like that theorem.
The above quote about the different meaning "trivial" can have in a mathematical sense is taken from Surely You're Joking, Mr. [BLANK]!, the autobiography of WHAT SCIENTIST who shared the 1965 Nobel Prize in Physics with Julian Schwinger and Sin-Itiro Tomonaga?
RICHARD FEYNMAN