S is any set. See also countable set, denumerably infinite set, finite set, infinite set, and uncountably infinite set.
carotenes Hydrocarbon carotenoids (a subclass of tetraterpenes).
carotenoids Tetraterpenoids (C40), formally derived from the acylic parent ψ,ψ-carotene I by hydrogenation, dehydrogenation, cyclization, oxidation, or combination of these processes. This class includes carotenes, xanthophylls, and certain compounds that arise from rearrangement of the skeleton of I or by loss of part of this structure. Retinoids are excluded.