Isabelle-extreme: Hot!

theory Scratch imports Main begin (* Define addition via fixed point *) definition add :: "nat ⇒ nat ⇒ nat" where "add ≡ fix (λadd n m. if n = 0 then m else add (n-1) (m+1))"

Have you experimented with minimal logics inside Isabelle? Share your experiences below! isabelle-extreme

end

isabelle extreme This opens a theory file with the extension .ext . Here’s a minimal example: theory Scratch imports Main begin (* Define addition

isabelle-extreme is the "assembly language" of the Isabelle ecosystem – raw, unforgiving, and beautiful in its simplicity. While you will never ship a verified compiler written in it, exploring it offers a rare glimpse into the foundational bedrock on which massive proof developments rest. isabelle-extreme