**Reduplication in Hebrew as a Diagnostic for Antonym Decomposition** *Ido Benbaji, Omri Doron, Ruoan Wang (MIT)* **Live Q&A session**: Sept 7, Monday, London time (BST) 6:30pm. Participants will be manually admitted. https://mit.zoom.us/j/8191904098 **Files**: Our recorded talk follows a set of slides. For convenience, we also provide a handout with the data and formal definitions. **Abstract:** In recent years, it has become increasingly common to decompose what have been called "marked members of antonym pairs" into a negation operator and the corresponding unmarked pair member (henceforth: negative and positive adjectives, cf. Büring 2007, Heim 2006; 2008). This approach contrasts with theories that, at least implicitly, assume the negative component in adjectives is lexicalized in their core meaning. We argue, based on evidence from Modern Hebrew reduplication, that we need a mixed analysis incorporating both approaches: some negative adjectives must be syntactically decomposable, while others are syntactically simplex. We test our analysis by examining cross-polar anomalies and Rullmann ambiguities.