收录日期:2019/10/18 22:08:55 时间:2015-01-31 22:10:50 标签:prolog

I've seen some answers here that use it and I don't know what it means or how to use it. I's also hard to look for it via a search engine :)

It's the 'not provable' operator. It succeeds if its argument is not provable (and fails if its argument is provable).

It's do with negation. \+ Goal will succeed if Goal cannot be proven.