Über dichte Ordnungstypen.
Über die Definition durch transfinite Induktion und verwandte Fragen der allgemeinen Mengenlehre
Über Mengen mit Trennrelationen
Über Teilsysteme von ...({g}).
Über zwei Bezeichnungssysteme für Ordinalzahlen.
Über zwei Sätze von G. Fichtenholz und L. Kantorovitch
Ueber ein Princip der Zuordnung algebraischer Formen.
Ultrafilter extensions of asymptotic density
We characterize for which ultrafilters on is the ultrafilter extension of the asymptotic density on natural numbers -additive on the quotient boolean algebra or satisfies similar additive condition on . These notions were defined in [Blass A., Frankiewicz R., Plebanek G., Ryll-Nardzewski C., A Note on extensions of asymptotic density, Proc. Amer. Math. Soc. 129 (2001), no. 11, 3313–3320] under the name (null) and (*). We also present a characterization of a - and semiselective ultrafilters...
Ultrafilter with predecessors in Rudin-Frolík order
Ultrafilters and endomorphic universes
Ultrafilters of sets
Ultrafilters over measurable cardinals
Ultrafilters without immediate predecessors in Rudin-Frolík order
Ultrafiltres absolus et problèmes d'extraction de sous-suites
Ultrapowers and Boolean ultrapowers of ... and ...1.
Ultraproducts and the axiom of choice
Un paseo alrededor de la teoría de conjuntos.
Un théorème en Algèbre et en Analyse.
Una classe di soluzioni con zeri dell'equazione funzionale di Aleksandrov.
In this paper we consider the Aleksandrov equation f(L + x) = f(L) + f(x) where L is contained in Rn and f: L --> R and we describe the class of solutions bounded from below, with zeros and assuming on the boundary of the set of zeros only values multiple of a fixed a > 0. This class is the natural generalization of that described by Aleksandrov itself in the one-dimensional case.
Una introducción a la W-calculabilidad: Operaciones básicas.
Our purpose is to introduce the W-composition, W-minimalization and W-primitive recursion operations as operations between W-valued functions, where W denotes the ordered semiring ([0,1],+,≤). We prove that: 1) the set of W-calculable functions is closed under the W-composition and W-primitice recursion operations, and 2) the set of the partially W-calculable functions is closed under the W-minimalization operation.