Proceedings of the Ninth Symposium on Logic and Language. 2006, 70-77
The imperfective aspect in Russian competes with the perfective in referring to events whose existence is entailed by the input context. In the first, major part of the paper (sections 1-5) I take a global view on aspectual competition, which is analyzed in light of various pragmatic constraints. It is shown in a bidirectional optimization how the default/unmarked imperfective in the appropriate context gets a presuppositional interpretation. Then, in the second part of the paper, I turn to the issue of how this presuppositional reading can be accounted for locally (compositionally) at the syntax-semantics interface, without assuming a proliferation of imperfective operators.