Chris Laskowski

Office: Room 3312, Mathematics Building
Office Phone: (301) 405-5336
Departmental Fax: (301) 314-0827
E-mail: mcl "at" math.umd.edu

Office hours

Teaching: Spring, 2024

Math 446, Set Theory MWF 1:00-1:50.

Research interests

My current research interest is model theory, broadly defined:

Classification theory

The number of nonisomorphic models

The uncountable spectra of countable theories, with B. Hart and E. Hrushovski, Annals of Mathematics 152 (2000) 207--257.   .ps   .pdf

• Classifiable theories

Unique decomposition in classifiable theories, with B. Hart and E. Hrushovski, Journal of Symbolic Logic 67 (2002) 61-68.   .ps   .pdf

Non-locally modular types in classifiable theories, with E. Bouscaren, B. Hart and E. Hrushovski, Journal of Mathematical Logic (submitted).   .pdf

• Karp complexity

The Karp compexity of unstable classes, with S. Shelah, Archive for Mathematical Logic 40(2001) 69-88.   .ps   .pdf

Karp complexity and classes with the independence property, with S. Shelah, Annals of Pure and Applied Logic 120(2003), 263--283.   .ps   .pdf

• Schröder-Bernstein property

The Schröder-Bernstein property for weakly minimal theories, with J. Goodrick, Israel Journal of Mathematics 188 (2012) 91-110.   .pdf
The Schröder-Bernstein property for a-saturated models, with J. Goodrick, Proc. AMS 142 (2014), no. 3, 1013-1023.   .pdf

• Strictly stable theories

A trichotomy of countable, stable, unsuperstable theories, with S. Shelah, Transactions AMS 363 (2011) 1619-1629.   .pdf

• Atomic models of countable, complete theories

Constructing many atomic models in aleph_1, with J. Baldwin and S. Shelah, Journal of Symbolic Logic 81 (2016), no. 3, 1142--1162.   .pdf

A strong failure of aleph_0-stability for atomic classes, with S. Shelah, Archive of Math Logic 58 (2019), Issue 1-2, 99-118.   .pdf

Henkin constructions of models with size continuum, with J. Baldwin, Bulletin of Symbolic Logic 25 (2019) 1-33.   .pdf

When does aleph1-categoricity imply omega-stability? with J. Baldwin and S. Shelah, Model Theory (to appear).

• Applications of Descriptive Set Theory

Descriptive set theory and uncountable model theory, in Logic Colloquium '03, Lecture Notes in Logic, 24 (2006) 133-145.   .ps   .pdf

Decompositions of saturated models of stable theories, with S. Shelah, Fundamenta Mathematicae 191 (2006) 95-124.   .pdf

• Borel complexity of first order theories

An old friend revisited: Countable models of omega-stable theories, Proceedings of the Vaught's Conjecture conference, Notre Dame Journal of Formal Logic 48(2007) 133--141.   .pdf

Conference Presentation (5 April, 2008) Omega-stable theories: Do uncountable languages matter?

P-NDOP and P-decompositions of aleph_epsilon saturated models of superstable theories, with S. Shelah, Fundamenta Mathematicae 229 (2015), no. 1, 47-81.   .pdf

Borel completeness of some aleph_0 stable theories, with S. Shelah, Fundamenta Mathematicae 229 (2015), no. 1, 1-46.   .pdf

Borel completeness and potential canonical Scott sentences, with D. Ulrich and R. Rast, Fundamenta Mathematicae 239 (2017), no. 2, 101-147.   .pdf

Most(?) first order theories have Borel complete reducts, with D. Ulrich, Journal of Symbolic Logic 88 (2023), no. 1, 418-426.   .pdf

Characterizing the existence of a Borel complete expansion, with D. Ulrich, Fundamenta Mathematicae 262 (2023) no. 1, 1-35.   .pdf

Borel complexity of modules, with D. Ulrich, Annals of Mathematics (submitted)   .pdf

• On Vaught's conjecture

Three red herrings around Vaught's conjecture, with J. Baldwin, S. Friedman, and M. Koerwien, Transactions AMS 368 (2016), no. 5, 3673-3694.   .pdf

Berkeley tutorial: Vaught's Conjecture 2015   Talk 1   Talk 2   Talk 3

• Bounding quantifier complexity in some trivial theories

Trivial, strongly minimal theories are model complete after naming constants, with S. Goncharov, V. Harizanov, S. Lempp and C. McCoy, Proc. AMS 131(2003), no. 12, 3901--3912.   .ps   .pdf

Model completeness for trivial, uncountably categorical theories of Morley rank one, with A. Dolich and A. Raichev, Archive for Math. Logic 45(2006) 931-945.   .pdf

On the computability-theoretic complexity of trivial, strongly minimal models, with B. Khoussainov, S. Lempp, and R. Solomon, Proc. AMS 135(2007), no. 11, 3711-3721.   .pdf

The elementary diagram of a trivial, weakly minimal structure is near model complete, Archive for Math. Logic 48(2009), no 1, 15--24.   .pdf

Mutually algebraic structures and expansions by predicates, Journal of Symbolic Logic 78 (2013), 185-194. .pdf

Characterizing model completeness among mutually algebraic structures, Notre Dame Journal of Formal Logic 56 (2015), no. 3, 463-470. .pdf

Conference Presentation (Cesme, Turkey, 20 May, 2012) Mutually algebraic structures and `automatic' quantifier elimination

Uniformly bounded arrays and mutually algebraic structures, with C. Terry, Notre Dame Journal of Formal Logic 61 (2020), no. 2, 265-282. .pdf

Mutual algebraicity and cellularity, with S. Braunfeld, Archive for Math Logic 61 (2022), no. 5-6, 841-857. .pdf

Theories with few non-algebraic types over models, and their decompositions, with S. Braunfeld, Proceedings AMS 150 (2022), no. 9, 4021-4026. .pdf

• Applications of mutual algebraicity

Jumps in speeds of hereditary properties in finite relational languages, with C. Terry, Journal of Combinatorial Theory, Series B 154 (2022), 93-135. .pdf

Weakly minimal groups with a new predicate, with G. Conant, Journal of Mathematical Logic 20 (2020), no. 2, 27 pp. .pdf

Counting siblings in universal theories, with S. Braunfeld, Journal of Symbolic Logic 87 (2022), no. 3, 1130-1155. .pdf

• Classification via monadic expansions

Characterizations of monadic NIP, with S. Braunfeld, Transactions of AMS, Series B, 8 (2021), 948-970. .pdf

Worst case expansions of complete theories, with S. Braunfeld, Model theory, 1 no. 1 (2022), 15-30. .pdf

Existential characterizations of monadic NIP, with S. Braunfeld, Communications of AMS (submitted).

• Hrushovski constructions and Fraisse constructions

A simpler axiomatization of the Shelah-Spencer almost sure theories, Israel Journal of Mathematics 161(2007), 157-186.   .pdf
On rational limits of Shelah-Spencer graphs, with Justin Brody, Journal of Symbolic Logic 77 (2012) 580-592.   .pdf
Disjoint amalgamation and Locally Finite AEC's, with John Baldwin and Martin Koerwien, Journal of Symbolic Logic   82 (2017) 98-119. .pdf

• Compression schemes and uniformly definable families

Compression schemes, stable definable families, and o-minimal structures, with H. Johnson, Discrete and computational geometry 43(2010), 914-926.   .pdf

Conference Presentation (Logic Colloquium 2010, Paris, 26 July, 2010) Compression schemes and definability of types in stable and dependent formulas

On VC-minimal theories and variants, with V. Guingona, Archive for Math Logic 52 (2013), no. 7-8, 743-758.   .pdf

• Ordered structures

Model companion of ordered theories with an automorphism, with K. Pal,   Transactions AMS 367 (2015), no. 10, 6877-6902.   .pdf

Definable choice for a class of weakly o-minimal theories, with C. Shaw,   Archive for Math Logic   55 (2016), no. 5-6, 735--748 .pdf

• Algebraic questions arising from fuzzy logics

A classification of BL-algebras, with Y.V. Shashoua, Fuzzy sets and systems 131(2002), 271--282.   .ps   .pdf

Generalized ordinal sums and BL-chains, with Y.V. Shashoua, Algebra Universalis 52(2004), 137-153.   .ps   .pdf

Provability in product logic, with S. Malekpour, Archive for Math. Logic 46(2007) 365--378.   .ps   .pdf

• Protein chemistry

Analysis of sequence-reactivity space for protein-protein interactions, with J. Li, Z. Yi, M. Laskowski, and C. Bailey-Kellogg, Proteins 58(3), 2005, 661-671.   .pdf

Functional evolution within a protein superfamily, with Z. Yi, O. Vitek, M.A. Qasim, W. Lu, M. Ranjbar, J. Li, M. Laskowski, Jr, and C. Bailey-Kellogg, Proteins 63(3), 2006, 697-708.   .pdf

(***) The above research was partially supported by NSF research grants DMS-9403701, 9704364, 0071746, 0300080, 0600217, 0901336, 1308546, 1855789 and 2154101.

---