Parity is a concept that has meaning only for fields or waves and therefore has meaning only in classical field theory or in quantum mechanics. See Quantum mechanics The conservation of parity follows from the inversion symmetry of space, that is, the invariance of the Schrödinger equation H&...
, confirming that the definition of parity for the rationals is an extension of the usual meaning for the integers. We see that the even and odd rationals respect the four `rules of parity’ listed above. The rational numbers are countable: they can be put into one-to-one corre...