Proper and piecewise proper families of reals
نویسندگان
چکیده
منابع مشابه
Bounded Proper Forcing Axiom and Well Orderings of the Reals
We show that the bounded proper forcing axiom BPFA implies that there is a well-ordering of P(ω1) which is ∆1 definable with parameter a subset of ω1. Our proof shows that if BPFA holds then any inner model of the universe of sets that correctly computes א2 and also satisfies BPFA must contain all subsets of ω1. We show as applications how to build minimal models of BPFA and that BPFA implies t...
متن کاملProper minor-closed families are small
We prove that for every proper minor-closed class I of graphs there exists a constant c such that for every integer n the class I includes at most n!c graphs with vertex-set {1, 2, . . . , n}. This answers a question of Welsh.
متن کاملProper Semirings and Proper Convex Functors
Esik and Maletti introduced the notion of a proper semiring and proved that some important (classes of) semirings – Noetherian semirings, natural numbers – are proper. Properness matters as the equivalence problem for weighted automata over a semiring which is proper and finitely and effectively presented is decidable. Milius generalised the notion of properness from a semiring to a functor. As...
متن کاملProper actions and proper invariant metrics
We show that if a locally compact group G acts properly on a locally compact σ-compact space X, then there is a family of G-invariant proper continuous finite-valued pseudometrics which induces the topology of X. If X is, furthermore, metrizable, then G acts properly on X if and only if there exists a G-invariant proper compatible metric on X.
متن کاملk-PROPER FAMILIES AND ALMOST APPROXIMATELY POLYNOMIAL FUNCTIONS
Using the notion of k-proper family we prove general results on the almost approximate stability of the polynomial functional equation. As one of the corollaries we obtain the generalization of the Theorem of R. Ger (cf. [4]): Theorem Let G be a uniquely n! divisible commutative semigroup and let I be a translation invariant proper ideal in G such that 1 i U ∈ I for every U ∈ I, i = 1, . . . , ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: MLQ
سال: 2009
ISSN: 0942-5616,1521-3870
DOI: 10.1002/malq.200810015