The gerund is the non-finite form of the verb which combines the properties of the verb and the noun. Similar to the infinitive, it serves as the verbal name of a process, but its substantive quality is stronger than that of the infinitive as the gerund can be modified by a noun in the possessive case or its pronominal equivalents and it can be used with prepositions.
The formal sign of the gerund is homonymous with that of the present participle: it is the suffix -ing added to its grammatically (categorially) leading element.
The gerund is a categorially changeable/variable/demutative form; it has two grammatical categories, sharing them with the finite verb and the present participle:
1) the aspective category of retrospective coordination (perfect in opposition),
2) the category of voice (passive in opposition).
The categorial paradigm of the gerund of the objective verb includes four forms:
the simple active taking
the perfect active having taken
the simple passive being taken
the perfect passive having been taken
The gerundial paradigm of the non-objective verb includes two forms.
going having gone.
The perfect forms of the gerund are used, as a rule, only in semantically strong positions.
The combinability of the gerund is dual (noun and verb features):
1) verb-type combinability: it combines with nouns expressing the object of the action; modifying adverbs; certain semi-functional predicator verbs (other than modal).
2) noun-type combinability: with finite notional verbs as the object of the action; finite notional verbs as the prepositional adjunct of various functions; finite notional verbs as the subject of the action; nouns as the prepositional adjunct of various functions.
The syntactic features of the gerund: the subject, the object, the predicative, the attribute, the adverbial modifier.