Browsing Department of Informatics by Author "Parmann, Erik"
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Case Studies in Constructive Mathematics
Parmann, Erik (Doctoral thesis, 2016-01-22)The common theme in this thesis is the study of constructive provability: in particular we investigate aspects of finite sets and Kan simplicial sets from a constructive perspective. There are numerous definitions of finiteness ... -
Investigating Streamless Sets
Parmann, Erik (Journal article; Peer reviewed, 2015)In this paper we look at streamless sets, recently investigated by Coquand and Spiwack. A set is streamless if every stream over that set contain a duplicate. It is an open question in constructive mathematics whether the ... -
Non-Constructivity in Kan Simplicial Sets
Bezem, Marc; Coquand, Thierry; Parmann, Erik (Journal article; Peer reviewed, 2015)We give an analysis of the non-constructivity of the following basic result: if X and Y are simplicial sets and Y has the Kan extension property, then Y X also has the Kan extension property. By means of Kripke countermodels ...