What's a good mathematical sets implementation in JavaScript?

Question

Where is a good mathematical sets implementation for JavaScript? It should include efficient implementations of intersection, union, complement, and (for bonus points) the Carte

Answer 1

Using Underscore's reduce method.

function cartesianProductOf(){
    return _.reduce(arguments, function(mtrx, vals){
        return _.reduce(vals, function(array, val){
            return array.concat(
                _.map(mtrx, function(row){ return row.concat(val); })
            );
        }, []);
    }, [[]]);
}