Roelcke non-precompactness, simplicity, and non-amenability of the automorphism group of the Fraïssé limit of finite Heyting algebras are proved among others.

We introduce prime products as a generalization of ultraproducts for positive logic. Prime products are shown to satisfy a version of Łoś’s Theorem restricted to positive formulas, as well as the following variant of the Keisler Isomorphism Theorem: under the generalized continuum hypothesis, two models have the same positive theory if and only if they have isomorphic prime powers of ultrapowers.

Previous studies reported that consumers choose a higher number of options in subtractive framing, which delete the unnecessary options from the full model with all options chosen than in additive framing, which adds options to a simple base model. The purposes of this study are to examine the effect of age on option framing and the differences of product type on the option framing effect using two product scenarios. Participants were 40 younger and 40 older adults. We measured the number (...) of options chosen, total price, choice difficulty, and choice satisfaction. In addition, cognitive functions were assessed. Results revealed that older and younger adults chose more options in the -OF condition for both the scenarios. For the medical examination, older adults chose more options than did the younger adults in both -OF and +OF conditions. Developmental shift in goals and motivation related to life-span may explain the differences between the age differences. (shrink)

We investigate the role of coalgebraic predicate logic, a logic for neighborhood frames first proposed by Chang, in the study of monotonic modal logics. We prove analogues of the Goldblatt–Thomason theorem and Fine’s canonicity theorem for classes of monotonic neighborhood frames closed under elementary equivalence in coalgebraic predicate logic. The elementary equivalence here can be relativized to the classes of monotonic, quasi-filter, augmented quasi-filter, filter, or augmented filter neighborhood frames, respectively. The original, Kripke-semantic versions of the theorems follow as a (...) special case concerning the classes of augmented filter neighborhood frames. (shrink)