Digital Reading and the Concept of Ebook: Metaphorical Analysis of Preservice Teachers’ Perceptions Regarding the Concept of Ebook

The aim of this study was to determine the metaphorical perceptions of preservice Turkish teachers (PTTs) regarding the concept of ebook. In accordance with this aim, answers to the questions of “What are the metaphors used by PTTs for the concept of e-book?” and “Under which categories could the metaphors used by PTTs for the concept of e-book be collected?” were sought. A total of 150 preservice teachers studying in the Faculty of Education, Turkish Education Department at Çukurova University, constituted the participants of the research designed according to the phenomenology design, one of the qualitative research methods. A semi-structured interview form was used as data collection tool. Data were analyzed using the content analysis technique. As a result of the study, it was determined that eight categories emerged from the metaphors produced by PTTs for ebook and that they mostly had positive meanings. These categories are, namely, facilitating, information source, accessible, portable, requirement, inadequate, attractive, and harmful. PTTs mostly produced metaphors for ebook in the facilitating category. It was followed by the information source and accessible categories. It was determined that some PTTs produced negative metaphors for ebooks, and these negative metaphors were collected under the inadequate and harmful categories.

Tameness, powerful images, and large cardinals

We provide comprehensive, level-by-level characterizations of large cardinals, in the range from weakly compact to strongly compact, by closure properties of powerful images of accessible functors. In the process, we show that these properties are also equivalent to various forms of tameness for abstract elementary classes. This systematizes and extends results of [W. Boney and S. Unger, Large cardinal axioms from tameness in AECs, Proc. Amer. Math. Soc. 145(10) (2017) 4517–4532; A. Brooke-Taylor and J. Rosický, Accessible images revisited, Proc. AMS 145(3) (2016) 1317–1327; M. Lieberman, A category-theoretic characterization of almost measurable cardinals (Submitted, 2018), http://arxiv.org/abs/1809.06963; M. Lieberman and J. Rosický, Classification theory for accessible categories. J. Symbolic Logic 81(1) (2016) 1647–1648].

WEAK SATURATION AND WEAK AMALGAMATION PROPERTY

We study the two model-theoretic concepts of weak saturation and weak amalgamation property in the context of accessible categories. We relate these two concepts providing sufficient conditions for existence and uniqueness of weakly saturated objects of an accessible category ${\cal K}$. We discuss the implications of this fact in classical model theory.

METRIC ABSTRACT ELEMENTARY CLASSES AS ACCESSIBLE CATEGORIES

We show that metric abstract elementary classes (mAECs) are, in the sense of [15], coherent accessible categories with directed colimits, with concrete ℵ1-directed colimits and concrete monomorphisms. More broadly, we define a notion of κ-concrete AEC—an AEC-like category in which only the κ-directed colimits need be concrete—and develop the theory of such categories, beginning with a category-theoretic analogue of Shelah’s Presentation Theorem and a proof of the existence of an Ehrenfeucht–Mostowski functor in case the category is large. For mAECs in particular, arguments refining those in [15] yield a proof that any categorical mAEC is μ-d-stable in many cardinals below the categoricity cardinal.

CLASSIFICATION THEORY FOR ACCESSIBLE CATEGORIES

We show that a number of results on abstract elementary classes (AECs) hold in accessible categories with concrete directed colimits. In particular, we prove a generalization of a recent result of Boney on tameness under a large cardinal assumption. We also show that such categories support a robust version of the Ehrenfeucht–Mostowski construction. This analysis has the added benefit of producing a purely language-free characterization of AECs, and highlights the precise role played by the coherence axiom.

Colimits of accessible categories

We show that any directed colimit of accessible categories and accessible full embeddings is accessible and, assuming the existence of arbitrarily large strongly compact cardinals, any directed colimit of accessible categories and accessible embeddings is accessible.

On Flat Objects of Finitely Accessible Categories

Flat objects of a finitely accessible additive category are described in terms of some objects of the associated functor category of , called strongly flat functors. We study closure properties of the class of strongly flat functors, and we use them to deduce the known result that every object of a finitely accessible abelian category has a flat cover.