Order:
Disambiguations
Steffen Lempp [67]S. Lempp [5]
  1.  38
    The d.r.e. degrees are not dense.S. Barry Cooper, Leo Harrington, Alistair H. Lachlan, Steffen Lempp & Robert I. Soare - 1991 - Annals of Pure and Applied Logic 55 (2):125-151.
    By constructing a maximal incomplete d.r.e. degree, the nondensity of the partial order of the d.r.e. degrees is established. An easy modification yields the nondensity of the n-r.e. degrees and of the ω-r.e. degrees.
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   29 citations  
  2.  21
    Universal computably enumerable equivalence relations.Uri Andrews, Steffen Lempp, Joseph S. Miller, Keng Meng Ng, Luca San Mauro & Andrea Sorbi - 2014 - Journal of Symbolic Logic 79 (1):60-88.
  3.  23
    The d.r.e. degrees are not dense.S. Cooper, Leo Harrington, Alistair Lachlan, Steffen Lempp & Robert Soare - 1991 - Annals of Pure and Applied Logic 55 (2):125-151.
    By constructing a maximal incomplete d.r.e. degree, the nondensity of the partial order of the d.r.e. degrees is established. An easy modification yields the nondensity of the n-r.e. degrees and of the ω-r.e. degrees.
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark   22 citations  
  4.  39
    A Δ20 set with no infinite low subset in either it or its complement.Rod Downey, Denis R. Hirschfeldt, Steffen Lempp & Reed Solomon - 2001 - Journal of Symbolic Logic 66 (3):1371-1381.
    We construct the set of the title, answering a question of Cholak, Jockusch, and Slaman [1], and discuss its connections with the study of the proof-theoretic strength and effective content of versions of Ramsey's Theorem. In particular, our result implies that every ω-model of RCA 0 + SRT 2 2 must contain a nonlow set.
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   9 citations  
  5.  33
    Highness and bounding minimal pairs.Rodney G. Downey, Steffen Lempp & Richard A. Shore - 1993 - Mathematical Logic Quarterly 39 (1):475-491.
  6.  16
    A finite lattice without critical triple that cannot be embedded into the enumerable Turing degrees.Steffen Lempp & Manuel Lerman - 1997 - Annals of Pure and Applied Logic 87 (2):167-185.
    We exhibit a finite lattice without critical triple that cannot be embedded into the enumerable Turing degrees. Our method promises to lead to a full characterization of the finite lattices embeddable into the enumerable Turing degrees.
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   13 citations  
  7. On extensions of embeddings into the enumeration degrees of the -sets.Steffen Lempp, Theodore A. Slaman & Andrea Sorbi - 2005 - Journal of Mathematical Logic 5 (02):247-298.
    We give an algorithm for deciding whether an embedding of a finite partial order [Formula: see text] into the enumeration degrees of the [Formula: see text]-sets can always be extended to an embedding of a finite partial order [Formula: see text].
    Direct download (5 more)  
     
    Export citation  
     
    Bookmark   4 citations  
  8.  29
    Computable categoricity of trees of finite height.Steffen Lempp, Charles McCoy, Russell Miller & Reed Solomon - 2005 - Journal of Symbolic Logic 70 (1):151-215.
    We characterize the structure of computably categorical trees of finite height, and prove that our criterion is both necessary and sufficient. Intuitively, the characterization is easiest to express in terms of isomorphisms of (possibly infinite) trees, but in fact it is equivalent to a Σ03-condition. We show that all trees which are not computably categorical have computable dimension ω. Finally, we prove that for every n≥ 1 in ω, there exists a computable tree of finite height which is δ0n+1-categorical but (...)
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   7 citations  
  9.  38
    Contiguity and Distributivity in the Enumerable Turing Degrees.Rodney G. Downey & Steffen Lempp - 1997 - Journal of Symbolic Logic 62 (4):1215-1240.
    We prove that a enumerable degree is contiguous iff it is locally distributive. This settles a twenty-year old question going back to Ladner and Sasso. We also prove that strong contiguity and contiguity coincide, settling a question of the first author, and prove that no $m$-topped degree is contiguous, settling a question of the first author and Carl Jockusch [11]. Finally, we prove some results concerning local distributivity and relativized weak truth table reducibility.
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   5 citations  
  10.  32
    Comparing DNR and WWKL.Klaus Ambos-Spies, Bjørn Kjos-Hanssen, Steffen Lempp & Theodore A. Slaman - 2004 - Journal of Symbolic Logic 69 (4):1089-1104.
    In Reverse Mathematics, the axiom system DNR, asserting the existence of diagonally non-recursive functions, is strictly weaker than WWKL0.
    Direct download (5 more)  
     
    Export citation  
     
    Bookmark   5 citations  
  11. Stability and Posets.Carl G. Jockusch, Bart Kastermans, Steffen Lempp, Manuel Lerman & Reed Solomon - 2009 - Journal of Symbolic Logic 74 (2):693-711.
    Hirschfeldt and Shore have introduced a notion of stability for infinite posets. We define an arguably more natural notion called weak stability, and we study the existence of infinite computable or low chains or antichains, and of infinite $\Pi _1^0 $ chains and antichains, in infinite computable stable and weakly stable posets. For example, we extend a result of Hirschfeldt and Shore to show that every infinite computable weakly stable poset contains either an infinite low chain or an infinite computable (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  12.  59
    A decomposition of the Rogers semilattice of a family of d.c.e. sets.Serikzhan A. Badaev & Steffen Lempp - 2009 - Journal of Symbolic Logic 74 (2):618-640.
    Khutoretskii's Theorem states that the Rogers semilattice of any family of c.e. sets has either at most one or infinitely many elements. A lemma in the inductive step of the proof shows that no Rogers semilattice can be partitioned into a principal ideal and a principal filter. We show that such a partitioning is possible for some family of d.c.e. sets. In fact, we construct a family of c.e. sets which, when viewed as a family of d.c.e. sets, has (up (...)
    Direct download (5 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  13.  8
    Reductions between types of numberings.Ian Herbert, Sanjay Jain, Steffen Lempp, Manat Mustafa & Frank Stephan - 2019 - Annals of Pure and Applied Logic 170 (12):102716.
    This paper considers reductions between types of numberings; these reductions preserve the Rogers Semilattice of the numberings reduced and also preserve the number of minimal and positive degrees in their semilattice. It is shown how to use these reductions to simplify some constructions of specific semilattices. Furthermore, it is shown that for the basic types of numberings, one can reduce the left-r.e. numberings to the r.e. numberings and the k-r.e. numberings to the k+1-r.e. numberings; all further reductions are obtained by (...)
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark   1 citation  
  14.  24
    Filters on Computable Posets.Steffen Lempp & Carl Mummert - 2006 - Notre Dame Journal of Formal Logic 47 (4):479-485.
    We explore the problem of constructing maximal and unbounded filters on computable posets. We obtain both computability results and reverse mathematics results. A maximal filter is one that does not extend to a larger filter. We show that every computable poset has a \Delta^0_2 maximal filter, and there is a computable poset with no \Pi^0_1 or \Sigma^0_1 maximal filter. There is a computable poset on which every maximal filter is Turing complete. We obtain the reverse mathematics result that the principle (...)
    Direct download (5 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  15.  44
    The undecidability of the II4 theory for the R. E. wtt and Turing degrees.Steffen Lempp & André Nies - 1995 - Journal of Symbolic Logic 60 (4):1118 - 1136.
    We show that the Π 4 -theory of the partial order of recursively enumerable weak truth-table degrees is undecidable, and give a new proof of the similar fact for r.e. T-degrees. This is accomplished by introducing a new coding scheme which consists in defining the class of finite bipartite graphs with parameters.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  16.  51
    On Computable Self-Embeddings of Computable Linear Orderings.Rodney G. Downey, Bart Kastermans & Steffen Lempp - 2009 - Journal of Symbolic Logic 74 (4):1352 - 1366.
    We solve a longstanding question of Rosenstein, and make progress toward solving a longstanding open problem in the area of computable linear orderings by showing that every computable ƞ-like linear ordering without an infinite strongly ƞ-like interval has a computable copy without nontrivial computable self-embedding. The precise characterization of those computable linear orderings which have computable copies without nontrivial computable self-embedding remains open.
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  17.  51
    A general framework for priority arguments.Steffen Lempp & Manuel Lerman - 1995 - Bulletin of Symbolic Logic 1 (2):189-201.
    The degrees of unsolvability were introduced in the ground-breaking papers of Post [20] and Kleene and Post [7] as an attempt to measure theinformation contentof sets of natural numbers. Kleene and Post were interested in the relative complexity of decision problems arising naturally in mathematics; in particular, they wished to know when a solution to one decision problem contained the information necessary to solve a second decision problem. As decision problems can be coded by sets of natural numbers, this question (...)
    Direct download (10 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  18.  36
    On the complexity of the successivity relation in computable linear orderings.Rod Downey, Steffen Lempp & Guohua Wu - 2010 - Journal of Mathematical Logic 10 (1):83-99.
    In this paper, we solve a long-standing open question, about the spectrum of the successivity relation on a computable linear ordering. We show that if a computable linear ordering [Formula: see text] has infinitely many successivities, then the spectrum of the successivity relation is closed upwards in the computably enumerable Turing degrees. To do this, we use a new method of constructing [Formula: see text]-isomorphisms, which has already found other applications such as Downey, Kastermans and Lempp [9] and is of (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  19.  55
    Decidability of the two-quantifier theory of the recursively enumerable weak truth-table degrees and other distributive upper semi-lattices.Klaus Ambos-Spies, Peter A. Fejer, Steffen Lempp & Manuel Lerman - 1996 - Journal of Symbolic Logic 61 (3):880-905.
    We give a decision procedure for the ∀∃-theory of the weak truth-table (wtt) degrees of the recursively enumerable sets. The key to this decision procedure is a characterization of the finite lattices which can be embedded into the r.e. wtt-degrees by a map which preserves the least and greatest elements: a finite lattice has such an embedding if and only if it is distributive and the ideal generated by its cappable elements and the filter generated by its cuppable elements are (...)
    Direct download (10 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  20.  38
    The Undecidability of the II$^_4$ Theory for the R. E. Wtt and Turing Degrees.Steffen Lempp & André Nies - 1995 - Journal of Symbolic Logic 60 (4):1118-1136.
    We show that the $\Pi_4$-theory of the partial order of recursively enumerable weak truth-table degrees is undecidable, and give a new proof of the similar fact for r.e. T-degrees. This is accomplished by introducing a new coding scheme which consists in defining the class of finite bipartite graphs with parameters.
    Direct download (6 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  21. On the filter of computably enumerable supersets of an r-maximal set.Steffen Lempp, André Nies & D. Reed Solomon - 2001 - Archive for Mathematical Logic 40 (6):415-423.
    We study the filter ℒ*(A) of computably enumerable supersets (modulo finite sets) of an r-maximal set A and show that, for some such set A, the property of being cofinite in ℒ*(A) is still Σ0 3-complete. This implies that for this A, there is no uniformly computably enumerable “tower” of sets exhausting exactly the coinfinite sets in ℒ*(A).
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  22.  26
    A limit on relative genericity in the recursively enumerable sets.Steffen Lempp & Theodore A. Slaman - 1989 - Journal of Symbolic Logic 54 (2):376-395.
    Work in the setting of the recursively enumerable sets and their Turing degrees. A set X is low if X', its Turning jump, is recursive in $\varnothing'$ and high if X' computes $\varnothing''$ . Attempting to find a property between being low and being recursive, Bickford and Mills produced the following definition. W is deep, if for each recursively enumerable set A, the jump of $A \bigoplus W$ is recursive in the jump of A. We prove that there are no (...)
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  23.  44
    On the existence of a strong minimal pair.George Barmpalias, Mingzhong Cai, Steffen Lempp & Theodore A. Slaman - 2015 - Journal of Mathematical Logic 15 (1):1550003.
    We show that there is a strong minimal pair in the computably enumerable Turing degrees, i.e. a pair of nonzero c.e. degrees a and b such that a∩b = 0 and for any nonzero c.e. degree x ≤ a, b ∪ x ≥ a.
    Direct download (7 more)  
     
    Export citation  
     
    Bookmark   1 citation  
  24.  5
    Maximal Towers and Ultrafilter Bases in Computability Theory.Steffen Lempp, Joseph S. Miller, André Nies & Mariya I. Soskova - forthcoming - Journal of Symbolic Logic:1-21.
    The tower number ${\mathfrak t}$ and the ultrafilter number $\mathfrak {u}$ are cardinal characteristics from set theory. They are based on combinatorial properties of classes of subsets of $\omega $ and the almost inclusion relation $\subseteq ^*$ between such subsets. We consider analogs of these cardinal characteristics in computability theory. We say that a sequence $(G_n)_{n \in {\mathbb N}}$ of computable sets is a tower if $G_0 = {\mathbb N}$, $G_{n+1} \subseteq ^* G_n$, and $G_n\smallsetminus G_{n+1}$ is infinite for each (...)
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark  
  25.  8
    Bezem, M., see Barendsen, E.G. M. Bierman, M. DZamonja, S. Shelah, S. Feferman, G. Jiiger, M. A. Jahn, S. Lempp, Sui Yuefei, S. D. Leonhardi & D. Macpherson - 1996 - Annals of Pure and Applied Logic 79 (1):317.
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  26.  21
    Lowness for effective Hausdorff dimension.Steffen Lempp, Joseph S. Miller, Keng Meng Ng, Daniel D. Turetsky & Rebecca Weber - 2014 - Journal of Mathematical Logic 14 (2):1450011.
    We examine the sequences A that are low for dimension, i.e. those for which the effective dimension relative to A is the same as the unrelativized effective dimension. Lowness for dimension is a weakening of lowness for randomness, a central notion in effective randomness. By considering analogues of characterizations of lowness for randomness, we show that lowness for dimension can be characterized in several ways. It is equivalent to lowishness for randomness, namely, that every Martin-Löf random sequence has effective dimension (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   1 citation  
  27.  28
    Jumps of nontrivial splittings of recursively enumerable sets.Michael A. Ingrassia & Steffen Lempp - 1990 - Zeitschrift fur mathematische Logik und Grundlagen der Mathematik 36 (4):285-292.
  28.  33
    Jumps of nontrivial splittings of recursively enumerable sets.Michael A. Ingrassia & Steffen Lempp - 1990 - Mathematical Logic Quarterly 36 (4):285-292.
  29.  31
    The existential theory of the poset of R.e. Degrees with a predicate for single jump reducibility.Steffen Lempp & Manuel Lerman - 1992 - Journal of Symbolic Logic 57 (3):1120-1130.
    We show the decidability of the existential theory of the recursively enumerable degrees in the language of Turing reducibility, Turing reducibility of the Turing jumps, and least and greatest element.
    Direct download (8 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  30.  53
    Embedding finite lattices into the Σ20 enumeration degrees.Steffen Lempp & Andrea Sorbi - 2002 - Journal of Symbolic Logic 67 (1):69-90.
    We show that every finite lattice is embeddable into the Σ 0 2 enumeration degrees via a lattice-theoretic embedding which preserves 0 and 1.
    Direct download (6 more)  
     
    Export citation  
     
    Bookmark  
  31.  27
    Interpolating d-r.e. and REA degrees between r.e. degrees.Marat Arslanov, Steffen Lempp & Richard A. Shore - 1996 - Annals of Pure and Applied Logic 78 (1-3):29-56.
    We provide three new results about interpolating 2-r.e. or 2-REA degrees between given r.e. degrees: Proposition 1.13. If c h are r.e. , c is low and h is high, then there is an a h which is REA in c but not r.e. Theorem 2.1. For all high r.e. degrees h g there is a properly d-r.e. degree a such that h a g and a is r.e. in h . Theorem 3.1. There is an incomplete nonrecursive r.e. A (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark   2 citations  
  32.  44
    Heinz-Dieter Ebbinghaus, Jörg Flum, and Wolfgang Thomas. Einführung in die mathematische Logik. Die Mathematik. Wissenschaftliche Buchgesellschaft, Darmstadt1978, ix + 288 pp. - H.-D. Ebbinghaus, J. Flum, and W. Thomas. Mathematical logic. Revised English translation by Ann S. Ferebee of the preceding. Undergraduate texts in mathematics. Springer-Verlag, New York, Berlin, Heidelberg, and Tokyo, 1984, ix + 216 pp. - Heinz-Dieter Ebbinghaus, Jörg Flum, and Wolfgang Thomas. Einführung in die mathematische Logik. Second edition. Die Mathematik. Wissenschaftliche Buchgesellschaft, Darmstadt1986, ix + 308 pp. - H.-D. Ebbinghaus, J. Flum, and W. Thomas. Mathematical logic. Second edition. Revised English translation by Ann S. Ferebee and Margit Meßmer of the preceding. Undergraduate texts in mathematics. Springer-Verlag, New York, Berlin, Heidelberg, etc., 1994, x + 289 pp. [REVIEW]Steffen Lempp - 1995 - Journal of Symbolic Logic 60 (3):1013-1014.
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark  
  33.  2
    Archangel&y, DA, Dekhtyar, MI and Taitslin, MA, Linear logic for.M. A. Arslanov, S. Lempp, R. A. Shore, S. Artemov, V. Krupski, A. Dabrowski, L. S. Moss, R. Parikh, T. Eiter & G. Gottlob - 1996 - Annals of Pure and Applied Logic 78 (1-3):271.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark   3 citations  
  34.  30
    Ulrich Felgner. Das Induktions-Prinzip. Jahresbericht der Deutschen Mathematiker-Vereinigung. vol. 114, no. 1 , pp. 23–45. - Ulrich Felgner. Hilbert’s “Grundlagen der Geometrie” und ihre Stellung in der Geschichte der Grundlagendiskussion. Jahresbericht der Deutschen Mathematiker-Vereinigung. vol. 115, no. 3-4 , pp. 185–206. [REVIEW]Steffen Lempp - 2014 - Bulletin of Symbolic Logic 20 (2):201-202.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  35.  40
    Kenneth Kunen, The Foundations of Mathematics, Studies in Logic, Mathematical Logic and Foundations, vol. 19. College Publications, London, 2009, vii + 251 pp. [REVIEW]Steffen Lempp - 2016 - Bulletin of Symbolic Logic 22 (2):287-288.
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark  
  36.  24
    Joseph R. Shoenfield. Recursion theory, Lecture notes in logic, no. 1. Springer-Verlag, Berlin, Heidelberg, New York, etc., 1993, v + 84 pp. [REVIEW]Steffen Lempp - 1994 - Journal of Symbolic Logic 59 (3):1105.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  37.  34
    Corrigendum: "On the complexity of the successivity relation in computable linear orderings".Rodney G. Downey, Steffen Lempp & Guohua Wu - 2017 - Journal of Mathematical Logic 17 (2):1792002.
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark  
  38.  45
    Winter meeting of the association for symbolic logic: San Antonio, 1993.Steffen Lempp - 1994 - Journal of Symbolic Logic 59 (2):720-729.
  39. Master Index to Volumes 71-80.K. A. Abrahamson, R. G. Downey, M. R. Fellows, A. W. Apter, M. Magidor, M. I. da ArchangelskyDekhtyar, M. A. Taitslin, M. A. Arslanov & S. Lempp - 1996 - Annals of Pure and Applied Logic 80:293-298.
    No categories
     
    Export citation  
     
    Bookmark  
  40.  1
    Recursion Theory and Complexity: Proceedings of the Kazan '97 Workshop, Kazan, Russia, July 14-19, 1997.M. M. Arslanov & Steffen Lempp (eds.) - 1999 - W. De Gruyter.
    This volume contains papers from the recursion theory session of the Kazan Workshop on Recursion and Complexity Theory. Recursion theory, the study of computability, is an area of mathematical logic that has traditionally been particularly strong in the United States and the former Soviet Union. This was the first workshop ever to bring together about 50 international experts in recursion theory from the United States, the former Soviet Union and Western Europe.
    Direct download  
     
    Export citation  
     
    Bookmark  
  41.  7
    Computability and the Symmetric Difference Operator.Uri Andrews, Peter M. Gerdes, Steffen Lempp, Joseph S. Miller & Noah D. Schweber - 2022 - Logic Journal of the IGPL 30 (3):499-518.
    Combinatorial operations on sets are almost never well defined on Turing degrees, a fact so obvious that counterexamples are worth exhibiting. The case we focus on is the symmetric-difference operator; there are pairs of degrees for which the symmetric-difference operation is well defined. Some examples can be extracted from the literature, e.g. from the existence of nonzero degrees with strong minimal covers. We focus on the case of incomparable r.e. degrees for which the symmetric-difference operation is well defined.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  42.  33
    Infima in the Recursively Enumerable Weak Truth Table Degrees.Rich Blaylock, Rod Downey & Steffen Lempp - 1997 - Notre Dame Journal of Formal Logic 38 (3):406-418.
    We show that for every nontrivial r.e. wtt-degree a, there are r.e. wtt-degrees b and c incomparable to a such that the infimum of a and b exists but the infimum of a and c fails to exist. This shows in particular that there are no strongly noncappable r.e. wtt-degrees, in contrast to the situation in the r.e. Turing degrees.
    Direct download (6 more)  
     
    Export citation  
     
    Bookmark  
  43.  27
    The lindenbaum algebra of the theory of the class of all finite models.Steffen Lempp, Mikhail Peretyat'kin & Reed Solomon - 2002 - Journal of Mathematical Logic 2 (02):145-225.
    In this paper, we investigate the Lindenbaum algebra ℒ of the theory T fin = Th of the class M fin of all finite models of a finite rich signature. We prove that this algebra is an atomic Boolean algebra while its Gödel numeration γ is a [Formula: see text]-numeration. Moreover, the quotient algebra /ℱ, γ/ℱ) modulo the Fréchet ideal ℱ is a [Formula: see text]-algebra, which is universal over the class of all [Formula: see text] Boolean algebras. These conditions (...)
    Direct download (4 more)  
     
    Export citation  
     
    Bookmark  
  44.  28
    There is no plus-capping degree.Rodney G. Downey & Steffen Lempp - 1994 - Archive for Mathematical Logic 33 (2):109-119.
    Answering a question of Per Lindström, we show that there is no “plus-capping” degree, i.e. that for any incomplete r.e. degreew, there is an incomplete r.e. degreea>w such that there is no r.e. degreev>w witha∩v=w.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
  45.  27
    Copies of books to asl, box 742, vassar college, 124 Raymond avenue, poughkeepsie, ny 12604, usa. In a review, a reference “jsl xliii 148,” for example, refers either to the publication reviewed on page 148 of volume 43 of the journal, or to the review itself (which contains full bibliographical information for the reviewed publication). Analogously, a reference. [REVIEW]Anuj Dawar Colyvan, Steffen Lempp, Rahim Moosa, Ernest Schimmerling & Alex Simpson - 2013 - Bulletin of Symbolic Logic 19 (2).
    Direct download  
     
    Export citation  
     
    Bookmark  
  46.  22
    The Palmer House Hilton Hotel, Chicago, Illinois April 19–21, 2007.Yiannis Moschovakis, Richmond H. Thomason, Steffen Lempp, Steve Awodey, Jean-Pierre Marquis & William Tait - 2007 - Bulletin of Symbolic Logic 13 (4).
    Direct download  
     
    Export citation  
     
    Bookmark  
  47.  16
    Computability and uncountable linear orders II: Degree spectra.Noam Greenberg, Asher M. Kach, Steffen Lempp & Daniel D. Turetsky - 2015 - Journal of Symbolic Logic 80 (1):145-178.
  48.  6
    Computable linear orders and products.Andrey N. Frolov, Steffen Lempp, Keng Meng Ng & Guohua Wu - 2020 - Journal of Symbolic Logic 85 (2):605-623.
    We characterize the linear order types $\tau $ with the property that given any countable linear order $\mathcal {L}$, $\tau \cdot \mathcal {L}$ is a computable linear order iff $\mathcal {L}$ is a computable linear order, as exactly the finite nonempty order types.
    Direct download (2 more)  
     
    Export citation  
     
    Bookmark  
  49.  20
    Conference on Computability, Complexity and Randomness.Verónica Becher, C. T. Chong, Rod Downey, Noam Greenberg, Antonin Kucera, Bjørn Kjos-Hanssen, Steffen Lempp, Antonio Montalbán, Jan Reimann & Stephen Simpson - 2008 - Bulletin of Symbolic Logic 14 (4):548-549.
  50.  23
    A δ02 set with barely σ02 degree.Rod Downey, Geoffrey Laforte & Steffen Lempp - 1999 - Journal of Symbolic Logic 64 (4):1700 - 1718.
    We construct a Δ 0 2 degree which fails to be computably enumerable in any computably enumerable set strictly below $\emptyset'$.
    Direct download (3 more)  
     
    Export citation  
     
    Bookmark  
1 — 50 / 67