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APAL
2010
125views more  APAL 2010»
13 years 11 months ago
The computable Lipschitz degrees of computably enumerable sets are not dense
The computable Lipschitz reducibility was introduced by Downey, Hirschfeldt and LaForte under the name of strong weak truthtable reducibility [6]. This reducibility measures both t...
Adam R. Day
APAL
2010
113views more  APAL 2010»
13 years 11 months ago
Logic for update products and steps into the past
This paper provides a sound and complete proof system for a language Le+Y that adds to Dynamic Epistemic Logic (DEL) a discrete previous-time operator as well as single symbol for...
Joshua Sack
APAL
2010
69views more  APAL 2010»
13 years 11 months ago
Cardinal sequences of LCS spaces under GCH
Let C() denote the class of all cardinal sequences of length associated with compact scattered spaces. Also put C() = {f C() : f(0) = = min[f() : < ]}. If is a cardinal an...
Juan Carlos Martinez, Lajos Soukup
APAL
2010
68views more  APAL 2010»
13 years 11 months ago
Spaces of orders and their Turing degree spectra
We investigate computability theoretic and topological properties of spaces of orders on computable orderable groups. A left order on a group G is a linear order of the domain of ...
Malgorzata A. Dabkowska, Mieczyslaw K. Dabkowski, ...
APAL
2010
117views more  APAL 2010»
13 years 11 months ago
Club-guessing, stationary reflection, and coloring theorems
We obtain very strong coloring theorems at successors of singular cardinals from failures of certain instances of simultaneous reflection of stationary sets. In particular, the sim...
Todd Eisworth
APAL
2010
79views more  APAL 2010»
13 years 11 months ago
Martin's Axiom and embeddings of upper semi-lattices into the Turing degrees
It is shown that every locally countable upper semi-lattice of cardinality continuum can be embedded into the Turing degrees, assuming Martin's Axiom.
Wang Wei
APAL
2010
123views more  APAL 2010»
13 years 11 months ago
Cut elimination and strong separation for substructural logics: An algebraic approach
Abstract. We develop a general algebraic and proof-theoretic study of substructural logics that may lack associativity, along with other structural rules. Our study extends existin...
Nikolaos Galatos, Hiroakira Ono
APAL
2010
96views more  APAL 2010»
13 years 11 months ago
Light Dialectica revisited
We upgrade the light Dialectica interpretation [6] by adding two more light universal quantifiers, which are both semi-computational and semi-uniform and complement each other. An...
Mircea-Dan Hernest, Trifon Trifonov
APAL
2010
68views more  APAL 2010»
13 years 11 months ago
Higher Kurtz randomness
A real x is 1 1-Kurtz random (1 1-Kurtz random) if it is in no closed null 1 1 set (1 1 set). We show that there is a cone of 1 1-Kurtz random hyperdegrees. We characterize lowness...
Bjørn Kjos-Hanssen, André Nies, Fran...
APAL
2010
98views more  APAL 2010»
13 years 11 months ago
Classical proof forestry
Classical proof forests are a proof formalism for first-order classical logic based on Herbrand's Theorem and backtracking games in the style of Coquand. First described by M...
Willem Heijltjes