When properly examined in light of the Clifford algebra, these are naturally anti-commuting, that is, one has that w j w m = − − w m w j . This can be happily interpreted as the mathematical realization of the Pauli exclusion principle, thus allowing these abstractly defined formal structures to be interpreted as fermions. For ( p , q ) = ( 1 , 3 ) dimensional Minkowski space-time, there are only two such spinors possible, by convention labelled "left" and "right", as described above. A more formal, general presentation of Weyl spinors can be found in the article on the spin group.