21. The commutativity corresponds to the uniqueness of a map between two objects in a poset category. 22. More instructive is to check commutativity of the second element with E _ { ij }. 23. The so-called " natural " arithmetical operations retain commutativity at the expense of continuity. 24. The commutativity and associativity of rational addition is an easy consequence of the laws of integer arithmetic. 25. The zero-point energy of the field arises formally from the non-commutativity of and. 26. "Commutativity " is a property of some logical connectives of truth functional propositional logic. 27. This commutativity isomorphism encodes the " rule of signs " that is essential to super linear algebra. 28. Pointwise operations inherit such properties as associativity, commutativity and distributivity from corresponding operations on the codomain. 29. Obviously there is no commutativity otherwise Dx = xD, but I don't understand why. 30. Due to the non-commutativity of the matrix product, the rotation system must be ordered.
