Irene Heim : biography
Irene Roswitha Heim is a linguist and noted specialist in semantics. She was a professor at the University of Texas at Austin and UCLA before finally moving to the Massachusetts Institute of Technology in 1989, where she is Professor of Linguistics and Head of the Linguistics Section of the Department of Linguistics and Philosophy.
She is probably most famous for her 1982 University of Massachusetts Amherst dissertation The semantics of definite and indefinite noun phrases. In the work she argued (developing an insight by the philosopher David Lewis) that indefinite noun phrases like a cat in the sentence If a cat is not in Athens, she is in Rhodes are not quantifiers but free variables bound by an existential operator inserted in the sentence by a semantic operation that she dubbed existential closure.
She is also the co-author with Angelika Kratzer of one of the most influential textbooks of formal semantics, and is a co-editor (also with Kratzer) of the journal Natural Language Semantics.