What is TGG?

Transformational Generative Grammar

From late fifties onwards, the American linguist Noam Chomsky established a number of objectives that have continued to direct the linguistic research to the present day.

A very important notion which is central to Chomsky’s approach is that of well-formed sentence. Any theory that is capable of producing well-formed sentences and rejecting ill-formed sentences is referred to GENERATIVE GRAMMAR.
Thus, GENERATIVE GRAMMAR is a linguistic theory that regards grammar as a system of rules that generate the combinations of words that form grammatical sentences in a given language.

Instead of analyzing a single sentence, this grammar devises a set of rules of construction that may help in generating sentences or structures that are infinitely large in number.

It is “a type of grammar which describes a language by giving a set of rules which can be used to produce all the possible sentences in that language”

Oxford Dictionary
Generative Grammar ===? 1. Sentence
2. Competence
3. Components

1. Sentence:

The simplest syntactic theory is a grammar that consists of a list of all the well-formed sentences in a language. But, such a list would be too long as there is infinite number of sentences in any language.