142 research outputs found
On Hanf numbers of the infinitary order property
We study several cardinal, and ordinal--valued functions that are relatives
of Hanf numbers. Let kappa be an infinite cardinal, and let T subseteq
L_{kappa^+, omega} be a theory of cardinality <= kappa, and let gamma be an
ordinal >= kappa^+. For example we look at (1) mu_{T}^*(gamma, kappa):= min
{mu^* for all phi in L_{infinity, omega}, with rk(phi)< gamma, if T has the
(phi, mu^*)-order property then there exists a formula phi'(x;y) in L_{kappa^+,
omega}, such that for every chi >= kappa, T has the (phi', chi)-order
property}; and (2) mu^*(gamma, kappa):= sup{mu_T^*(gamma, kappa)| T in
L_{kappa^+,omega}}
A presentation theorem for continuous logic and Metric Abstract Elementary Classes
We give a presentation theorem for continuous first-order logic and Metric
Abstract Elementary classes in terms of and Abstract
Elementary Classes, respectively. This presentation is accomplished by
analyzing dense subsets that are closed under functions. We extend this
correspondence to types and saturation
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