GA (http://www.lojban.org/en/publications/reference_grammar/chapter14.html)

Indicates the beginning of two logically connected sumti, bridi-tails, or various
other things. Logical connections include ``both ... and'', ``either ... or'',
``if ... then'', and so on. See GI.

ga la djan. nanmu gi la djeimyz. ninmu Either John is a man or James is a
woman (or both).

