Greta Gerwig and Lola Kirke navigate the pitiless maw.

Greta Gerwig and Lola Kirke navigate the pitiless maw.

Leaving the comfort and familiarity of home for college is scary enough, but entering the pitiless maw of New York City makes it doubly so. In his third collaboration with writer/actress/lady-love Greta Gerwig, Noah Baumbach serves up a scenario in which a naive freshman has a secret weapon: an older pseudo-sister to help her navigate the city as an independent adult…