function multiplication(){
return u.slice(arguments).reduce(function(A, B, index){
if ( ! Array.isArray(A[0]) ) A = [A]
if ( ! Array.isArray(B[0]) ) B = u.partition(B, 1)
var height = A.length-1
, width = (B = transpose(B)).length-1
, result = u.span(0, height).map(function(i){
return u.span(0, width).map(function(j){
return m.dot(A[i],B[j])
})
})
;
if ( result[0].length == 1) result = Array.prototype.concat.apply([],result)
if ( result.length == 1 ) result = result[0]
return result
})
}
function subtraction(){
return u.slice(arguments).reduce(function(p, c, i){
return u.zipWith(m.sub, p, c)
})
}
function addition(){
return u.slice(arguments).reduce(function(p, c, i){
return u.zipWith(m.add, p, c)
})
}