@jim22k what did you intend to write here? Monoids must be associative--rearranging parentheses--which is very important. In addition, GraphBLAS monoids are typically (and really only make sense to be) commutative, but this only a strict requirement when creating a semiring from a monoid. For example, (a + b) + c equals (c + b) + a.

I was meaning commutative. Sorry for using the wrong terminology.
@eriknw should we list specifically which monoids are not associative? I think it's just first and last.

first and last aren't monoids, and all builtin monoids are both associative and commutative. I think we should mention both associativity and commutivity.

If you wanted a compact phrasing, you could say that

• associative = the order of operations does not matter
• commutative = the order of operands does not matter

But I don't think this is actually useful for someone who doesn't already know what associative and commutative mean.

I'm really sorry about the long delay, I expect to finish by Sunday. The package is in a very good shape, so there won't be requests for major changes.

Sounds good @szhorvat, and thanks again!

Also, thanks for carefully reading the docs and raising this issue. Fixing in #469.