My favorite is apple pie.
Is it correct? Can the adjective be a subject in an English sentence?
My favorite is apple pie.
Is it correct? Can the adjective be a subject in an English sentence?
In "My favorite is apple pie," the word favorite is, on what I think is the most likely interpretation, just a noun. But more generally, yes, a sentence can have an adjective as its subject. (Note that in the below I'm following the terminology of Huddleston & Pullum (2002).)
First, an adjective phrase can serve as the subject of the so-called "specifying be," where the subject expresses the value of a variable, as in sentences like "Ugly is what I'd call it" or "Angry is how I felt" (Huddleston & Pullum (2002), p. 268, 1422). In those sentences, ugly and angry are adjective phrases (consisting of single adjectives), each acting as the subject of to be.
The second case occurs when a sentence's subject is a noun phrase, but where that noun phrase is headed, not by a noun, but by an adjective serving as a "fused modifier-head" (ibid., p. 416-418). These occur in sentences like "There are many skyscrapers in the world, but the tallest stands in Dubai," where tallest is an adjective but it acts as the head of the noun phrase the tallest, which in turn is the subject of stands.
One might think that a sentence like "Even better was her third novel" also contains an adjective acting as a subject, but that is not so (ibid., p. 268). You can see this from the fact that the verb agrees with novel; if we make it plural, the verb becomes plural also: "Even better were her later novels." This is also obvious from the fact that the sentence can't undergo subject-auxiliary inversion with that word order intact: * "Was even better her third novel?" is ungrammatical. Instead, such sentences are examples of subject-dependent inversion, similar to sentences like "On the manager's desk sat a large manila envelope" (ibid., p. 1385-1389).
Nominal ellipsis.
As in:
McCarthy (1991:43) supposes that ellipsis is the omission of elements normally required by the grammar which is the speaker/writer assumes are obvious from the context and therefore need not be raised. This is not to say that every utterance which is not fully explicit is elliptical; most messages require some inputs from the context to make sense of them. Ellipsis is distinguished by the structure having some "missing" elements, for example, when there is a written sentence: Nellly [sic: typo?] liked the green tiles, I preferred the blue. For this type of the sentence, it is as nominal ellipsis because the word involves omission of noun headword.
See the full explanation for types of ellipsis here: ellipsis
Sample sentence: My favorite is apple pie.
Ellipsis: My favorite [pie] is apple pie.