It's used when talking about the extended Church-Turing thesis [1]: > "A probabilistic Turing machine can efficiently simulate any realistic model of computati

It's used when talking about the extended Church-Turing thesis [1]: > "A probabilistic Turing machine can efficiently simulate any realistic model of computation." The word 'efficiently' here means up to polynomial-time reductions. Real-world efficiency doesn't necessarily factor into what theoretical computer scientists are interested in. [1] https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis