@techreport{4ebabec3905b49628a9410f57ac9845d,
title = "The Admissible Rules of BD2 and GSc",
abstract = "The Visser rules form a basis of admissibility for the intuitionistic propositional calculus. We show how one can characterise the existence of covers in certain models, by means of formulae. Through this characterisation, we provide a new proof of the admissibility of a weak form of the Visser rules. Finally, we use this observation, coupled with a description of a generalisation of the disjunction property, to provide a basis of admissibility for the intermediate logics BD2 and GSc.",
author = "J.P. Goudsmit",
year = "2013",
month = sep,
day = "3",
language = "English",
publisher = "Logic Group preprint series: http://www.phil.uu.nl/preprints/lgps/",
type = "WorkingPaper",
institution = "Logic Group preprint series: http://www.phil.uu.nl/preprints/lgps/",
}