Seven Perfect Shuffles Randomize a Deck of Cards. But How Many Sloppy Ones?
(www.quantamagazine.org)
Wikipedia highlights this difference on their disambiguation page if you look up “Perfect Shuffle.”
It may refer to
- the Faro shuffle, in particular the interpretation whereby cards (or more generally, entities in sequence) are divided into two equal piles and interleaved.
Or
- Any shuffling algorithm that guarantees perfect randomness
I added bold because that’s the one we’re talking about.