Jovana Gajić (Göttingen)

English negated focused conjunction only has scalar alternatives, while its subdomain alternatives are not active (contra Magri 2014), otherwise the implicature computation would yield a contradiction after both simple and double exhaustification. Without the individual conjuncts in the computation, one round of exhaustification results in the well-known scalar implicature ''not both''. In contrast, the unfocused conjunction must make its individual conjuncts available for exhaustification. Coupled with Magri's (2014) account of homogeneity (Fodor 1970, Beck 2001), this can explain the ''expected both'' requirement which negated unfocused and seemingly displays (Szabolcsi and Haddican 2004). This effect is nothing else but a by-product of an independently needed mechanism of double exhaustification: the result of the second round of EXH, due to logical equivalences, states that, if one conjunct is false (NOT-P), then both conjuncts must be false (NOT[P-OR-Q]). Crucially, it is not designed as a presupposition, but it arises through implicatures. The role of negation is essential, as no double EXH would arise for andunF without a DE context. Competition takes place between the unfocused and the focused conjunction, through their respective implicature computations. Furthermore, the mismatch in the behavior between negated definite plurals and negated definite conjunctions, where the former do not display the ''expected both'' requirement, is now also accounted for by virtue of different strengthening procedures for the two cases: plurals start out as existentials and no subdomain alternatives are present in their computation (cf. Magri 2014), as opposed to andunF.

References:
Beck, S. (2001) Reciprocals are definites. Natural Language Semantics 9: 69-138.
Fodor, J. D. (1970) The linguistic description of opaque contexts. PhD thesis, MIT.
Magri, G. (2014) An account for the homogeneity effects triggered by plural definites and conjunction based on double strengthening. Pragmatics, Semantics and the Case of Scalar Implicatures, p. 99-145.
Szabolcsi, A., & Haddican, B. (2004). Conjunction Meets Negation: A Study in Cross-linguistic Variation. Journal of Semantics, 21(3): 219-249.