Gerunds are supposed to come after possesssives, but it is common to use object pronouns, and when these are used some grammarians call them fused participles.
I don't mind their coming. (Gerund)
I don't mind them coming. (Fused participle)
Irregular Verb; Auxiliary Verb; Ditransitive Verb; Dynamic Verb; Finite Verb; Inchoative Verb; Intransitive Verb; Modal Verb; Non-finite Verb; Phrasal Verb; Regular Verb; Stative Verb; Transitive Verb; Verb Group; Verb Phrase
Gerunds and Infinitives