[edflsafoiewq]

+ and = are pretty obvious but it can still be confusing. Take not=. Does (not= x y z) mean adjacent numbers are disequal (x≠y≠z, by analogy to + and =)? Or that no two numbers are equal? Or that at least two numbers are disequal? Different lisps pick different meanings.

[bjoli]

Which lisps? I think I have only ever seen that in clojure (thinking it was a bad idea), and clojure seems scared of parentheses. (not (equal? x y z)) is clearer, but suffers from the same drawback as your question.

The problem I think is that not= returns true as long as any elements are non-equal, which means it is not analogous to +. I can't speak for clojure, but this is in line with all equality predicates in scheme, negated or not. A predicate that checked if any neighbours are not equal would in true scheme spirit probably be called not-any-neighbour-equal? :)