trivially true theorem

noun phrase

1. A theorem whose truth is immediately clear from the definitions, assumptions, or a very simple argument, so it requires little or no substantial proof.

   B2

   countable

   • "The statement that every set is a subset of itself is a trivially true theorem."B2
   • "Because the result follows directly from the definition, the author calls it a trivially true theorem."C1
   • "In mathematics, a statement like '0 = 0' is considered a trivially true theorem."B2