The rule seems to apply to only an that is the ablaut alternant of . The character / was used for the alternant (or) operator. An alternant determinant is the determinant of a square alternant matrix. It is a structural isomer of the alternant PAH pyrene. Graphene can be considered an "infinite alternant" (only six-member carbon ring) polycyclic aromatic hydrocarbon (PAH). Trace alternant activity has been correlated with quiet sleep. It is fundamentally not an alternant hydrocarbon. Each of the various realizations is called an alternant. In this example, the vocalic alternant is realized as the off-glide of the diphthong . The trace alternant pattern has been correlated with quiet sleep in newborn babies. Both before and during labor, trace alternant patterns can be observed in the fetal EEG. An alternant hydrocarbon is any conjugated hydrocarbon system which does not possess an odd-membered ring. Those composed only of six-membered rings are called "alternant" PAHs, which include "benzenoid" PAHs. Two-player games housed in cocktails were usually alternant, each player taking turns.