what kind of adv and adj are these? what is prep. complement. Can you give ma a couple of examples of adj. and adv. which may function as prepositional complements?
The existence of adjectival or adverbial complements of prepositions is very improbable on purely conceptual grounds, because a) all true prepositions are two-place predicates, b) by definition, a predicate must take one or more arguments as its complements (broad sense, 'subjects' included), c) arguments must be encoded by referential expressions (names referring to 'entities', including time intervals, space regions or states of affairs) and d) both adjectives and adverbs are themselves predicates (of 'nominal' expressions in one case, of verbal or 'extended verbal' projections in the other), not arguments (note that they name nth-order properties, not individuals or situations).
Hence, all, or the great majority of, the cases of P+Adj or P+Adv you might think of if you just look up the part of speech of words in commercial dictionaries are not real adverbs (or adjectives). Typical examples are words like yesterday, today, tomorrow, now, then, here, there,... traditionally considered adverbs, but long ago reanalysed by serious syntacticians as NPs or deictics pointing to temporal or spatial regions. In some cases, their nominal character becomes obvious as soon as you consider that they may take genitive inflections (cf. yesterday's/today's/tomorrow's newspapers). In others (now, then, here, there,...) that evidence is not available for purely morphological or historical reasons (e.g., Modern English deictics do not inflect for case).
As to apparent P + Adj constructions, the evidence for 'nominal' status of the adjective is perhaps less compelling, and in some cases, there is no obvious analytical alternative yet, but some of those adjectives are the reflexes of translations from Latin (where 'altus'[> high], for example, was both an adjective and a noun meaning 'heaven' amongst other things), or nominalizations of a special kind (e.g., the use of guapo or listo in Spanish expressions like ir de guapo por la vida, pasarse de listo, etc.).
Apart from that, in many cases, the would-be P+Adj constructions have been re-analysed (at least within certain syntactic theories) and there is evidence that what seemed to be a preposition is not really such, but an 'inflectional' category or a complementizer (e.g., in English, the as or the for of consider somebody as intelligent, or take something for granted, etc.).
In general, thus, given the conceptual difficulties that the mere existence of P+Adj constructions raises, would-be cases of adjectival complements of prepositions probably result from the fact that most grammars have not yet analysed such constructions in sufficient depth, or, if some have, due to the fact that commercial dictionaries are very reluctant to change the 'part of speech' attributions that Greek, Latin and mediaeval grammarians established centuries or millennia ago and that remain in use in the elementary school grammars by which most of us learn the little we know about the syntax of our native languages.
Do these examples, "on high" as in The Lord our God who dwelleth on high (Psalms 63:5) (adjective prepositional complement) and from here as in "I can see your house from here" (adverb prepositional complement) count?
Have a look at this: http://languagetools.info/grammarpedia/prepphrase.htm