Traditional mathematical proofs often used high-level, concise arguments that omitted steps considered previously established.

“'Cause if you think about it, for many years, the way mathematical proofs were done were high up the abstraction mountain. So they would make these really high-level arguments, and it would just go without saying that certain arguments had been proved before, so you didn't need to go step by step, and it was very, very parsimonious.”