Optionally after the verb gam , the liṅ and the sic beginning with jhal consonants, in the ātmanepada , are kit,
The verb गम् 'to go' is Atmanepadi after the preposition सम् by Rule 1.3.29.
The result of its being kit is that the nasal is dropped in the Atmanepada, in forming the Aorist with सिच्, and the Bencdictive. Thus we have the forms :- संगंसीष्ट or संगसीष्ट in the Benedictive; and समगत or समगंस्त in the sich Aorist. These forms are thus evolved :-
सम् + गम् + सीष्ट = सम् + ग + सीष्ट 6.4.37 = संगसीष्ट 'may he combine.' Here the nasal म् of गम् is elided by treating the affix सीष्ट as कित् by Rule 6.4.37. In the alternative we have संगंसीष्ट.
So in the aorist सम् + गम् + सिच् + त = सम् + अट् + गम् + त 6.4.37 = समगत. The सिच् being elided by 8.2.27 (after a short inflective base, there is elision of सिच्, if a jhal follows). So when म् of गम् is elided by 6.4.37, there remains only ग which is a base ending in short अ, hence, the elision of सिच्. But in the alternative we have समगंस्त.,