Computable Presentability of Countable Linear Orders

Author(s):  
A. N. Frolov
Keyword(s):  
Author(s):  
Olivia Caramello

This chapter discusses several classical as well as new examples of theories of presheaf type from the perspective of the theory developed in the previous chapters. The known examples of theories of presheaf type that are revisited in the course of the chapter include the theory of intervals (classified by the topos of simplicial sets), the theory of linear orders, the theory of Diers fields, the theory of abstract circles (classified by the topos of cyclic sets) and the geometric theory of finite sets. The new examples include the theory of algebraic (or separable) extensions of a given field, the theory of locally finite groups, the theory of vector spaces with linear independence predicates and the theory of lattice-ordered abelian groups with strong unit.


2021 ◽  
pp. 1-39
Author(s):  
JUN LE GOH ◽  
ARNO PAULY ◽  
MANLIO VALENTI
Keyword(s):  

1995 ◽  
Vol 38 (2) ◽  
pp. 223-229
Author(s):  
John Lindsay Orr

AbstractA linearly ordered set A is said to shuffle into another linearly ordered set B if there is an order preserving surjection A —> B such that the preimage of each member of a cofinite subset of B has an arbitrary pre-defined finite cardinality. We show that every countable linearly ordered set shuffles into itself. This leads to consequences on transformations of subsets of the real numbers by order preserving maps.


1989 ◽  
Vol 54 (3) ◽  
pp. 865-874 ◽  
Author(s):  
Alain Louveau

AbstractWe prove two results about the embeddability relation between Borel linear orders: For η a countable ordinal, let 2η (resp. 2< η) be the set of sequences of zeros and ones of length η (resp. < η), equipped with the lexicographic ordering. Given a Borel linear order X and a countable ordinal ξ, we prove the following two facts.(a) Either X can be embedded (in a (X, ξ) way) in 2ωξ or 2ωξ + 1 continuously embeds in X.(b) Either X can embedded (in a (X, ξ) way) in 2<ωξ or 2ωξ continuously embeds in X. These results extend previous work of Harrington, Shelah and Marker.


2014 ◽  
Vol 79 (4) ◽  
pp. 1001-1019 ◽  
Author(s):  
ASHER M. KACH ◽  
ANTONIO MONTALBÁN

AbstractMany classes of structures have natural functions and relations on them: concatenation of linear orders, direct product of groups, disjoint union of equivalence structures, and so on. Here, we study the (un)decidability of the theory of several natural classes of structures with appropriate functions and relations. For some of these classes of structures, the resulting theory is decidable; for some of these classes of structures, the resulting theory is bi-interpretable with second-order arithmetic.


2011 ◽  
Vol 42 (3) ◽  
pp. 445-469 ◽  
Author(s):  
Sam Steddy ◽  
Vieri Samek-Lodovici

We propose an analysis that derives Cinque's (2005) typology of linear orders involving a demonstrative, numeral, adjective, and noun through four Optimality Theory constraints requiring leftward alignment of these items. We show that remnant movement is ungrammatical whenever it produces universally suboptimal alignments, compared with remnant-movement-free structures. Any movement is permitted, but only the best alignment configurations surface as grammatical. We also show that Cinque's original analysis must encode the structural derivations of all attested orders as parametric values of the associated languages. Our analysis need not make similar structural stipulations, as the different attested structures emerge from constraint reranking.


Author(s):  
Luca Aceto ◽  
Dario Della Monica ◽  
Anna Ingólfsdóttir ◽  
Angelo Montanari ◽  
Guido Sciavicco
Keyword(s):  

1997 ◽  
Vol 41 (2) ◽  
pp. 171-188 ◽  
Author(s):  
Jean-Paul Doignon ◽  
Michel Regenwetter

2001 ◽  
Vol 27 (8) ◽  
pp. 505-512 ◽  
Author(s):  
José Carlos Rodríguez Alcantud

We extend van Dalen and Wattel's (1973) characterization of orderable spaces and their subspaces by obtaining analogous results for two larger classes of topological spaces. This type of spaces are defined by considering preferences instead of linear orders in the former definitions, and possess topological properties similar to those of (totally) orderable spaces (cf. Alcantud, 1999). Our study provides particular consequences of relevance in mathematical economics; in particular, a condition equivalent to the existence of a continuous preference on a topological space is obtained.


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