Petr Hájek

According to our database, Petr Hájek authored at least 137 papers between 1966 and 2022.

Collaborative distances:

• Dijkstra number of three.
• Erdős number of three.

2022

How Much Propositional Logic Suffices for Rosser's Essential Undecidability Theorem?

Guillermo Badia, Petr Cintula, Petr Hájek, Andrew Tedder

Rev. Symb. Log., 2022

2013

Interpreting lattice-valued set theory in fuzzy set theory.

Petr Hájek, Zuzana Haniková

Log. J. IGPL, 2013

Some remarks on Cantor-Łukasiewicz fuzzy set theory.

Petr Hájek

Log. J. IGPL, 2013

On equality and natural numbers in Cantor-Łukasiewicz set theory.

Petr Hájek

Log. J. IGPL, 2013

2011

Comments on Interpretability and Decidability in Fuzzy Logic.

Petr Hájek

J. Log. Comput., 2011

Towards metamathematics of weak arithmetics over fuzzy logic.

Petr Hájek

Log. J. IGPL, 2011

Deductive Systems of Fuzzy Logic.

Petr Hájek

Proceedings of the Proof, Computation and Agency - Logic at the Crossroads., 2011

2010

Logics for Data Mining.

Petr Hájek

Proceedings of the Data Mining and Knowledge Discovery Handbook, 2nd ed., 2010

Some (non)tautologies of łukasiewicz and Product Logic.

Petr Hájek

Rev. Symb. Log., 2010

On witnessed models in fuzzy logic III - witnessed Gödel logics.

Petr Hájek

Math. Log. Q., 2010

On White's Expansion of Lukasiewicz Logic.

Petr Hájek

J. Log. Comput., 2010

The GUHA method and its meaning for data mining.

Petr Hájek, Martin Holena, Jan Rauch

J. Comput. Syst. Sci., 2010

On fuzzy modal logics S5(L).

Petr Hájek

Fuzzy Sets Syst., 2010

Editorial.

Siegfried Gottwald, Petr Hájek, Ulrich Höhle, Erich-Peter Klement

Fuzzy Sets Syst., 2010

Triangular norm based predicate fuzzy logics.

Petr Cintula, Petr Hájek

Fuzzy Sets Syst., 2010

2009

On Vagueness, Truth Values and Fuzzy Logics.

Petr Hájek

Stud Logica, 2009

Complexity Issues in Axiomatic Extensions of Lukasiewicz Logic.

Petr Cintula, Petr Hájek

J. Log. Comput., 2009

Arithmetical complexity of fuzzy predicate logics - A survey II.

Petr Hájek

Ann. Pure Appl. Log., 2009

2008

On copulas, quasicopulas and fuzzy logic.

Petr Hájek, Radko Mesiar

Soft Comput., 2008

On arithmetical complexity of fragments of prominent fuzzy predicate logics.

Petr Hájek

Soft Comput., 2008

Ontological Proofs of Existence and Non-Existence.

Petr Hájek

Stud Logica, 2008

A note on the first-order logic of complete BL-chains.

Petr Hájek, Franco Montagna

Math. Log. Q., 2008

Editorial.

Manuel Ojeda-Aciego, Siegfried Gottwald, Petr Hájek

Fuzzy Sets Syst., 2008

2007

On witnessed models in fuzzy logic II.

Petr Hájek

Math. Log. Q., 2007

On witnessed models in fuzzy logic.

Petr Hájek

Math. Log. Q., 2007

Mathematical Fuzzy Logic and Natural Numbers.

Petr Hájek

Fundam. Informaticae, 2007

Selected papers from the International Conference "The Logic of Soft Computing IV" and Fourth workshop of the ERCIM working group on soft computing.

Vilém Novák, Siegfried Gottwald, Petr Hájek

Fuzzy Sets Syst., 2007

Complexity of fuzzy probability logics II.

Petr Hájek

Fuzzy Sets Syst., 2007

Formal systems of fuzzy logic and their fragments.

Petr Cintula, Petr Hájek, Rostislav Horcík

Ann. Pure Appl. Log., 2007

Mathematical Fuzzy Logic - a Survey and Some News.

Petr Hájek

Proceedings of the New Dimensions in Fuzzy Logic and Related Technologies. Proceedings of the 5th EUSFLAT Conference, 2007

2006

Mathematical Fuzzy Logic - What It Can Learn from Mostowski and Rasiowa.

Petr Hájek

Stud Logica, 2006

On theories and models in fuzzy predicate logics.

Petr Cintula, Petr Hájek

J. Symb. Log., 2006

Computational complexity of t-norm based propositional fuzzy logics with rational truth constants.

Petr Hájek

Fuzzy Sets Syst., 2006

What is mathematical fuzzy logic.

Petr Hájek

Fuzzy Sets Syst., 2006

On Fuzzy Theories with Crisp Sentences.

Petr Hájek

Proceedings of the Algebraic and Proof-theoretic Aspects of Non-classical Logics, 2006

What does mathematical fuzzy logic offer to description logic?

Petr Hájek

Proceedings of the Fuzzy Logic and the Semantic Web, 2006

2005

Arithmetical complexity of fuzzy predicate logics - a survey.

Petr Hájek

Soft Comput., 2005

Fleas and Fuzzy Logic.

Petr Hájek

J. Multiple Valued Log. Soft Comput., 2005

A non-arithmetical Gödel logic.

Petr Hájek

Log. J. IGPL, 2005

Editorial.

Matthias Baaz, Agata Ciabattoni, Dov M. Gabbay, Petr Hájek

Log. J. IGPL, 2005

Making fuzzy description logic more general.

Petr Hájek

Fuzzy Sets Syst., 2005

Terminological difficulties in fuzzy set theory - The case of "Intuitionistic Fuzzy Sets".

Didier Dubois, Siegfried Gottwald, Petr Hájek, Janusz Kacprzyk, Henri Prade

Fuzzy Sets Syst., 2005

On arithmetic in the Cantor- Lukasiewicz fuzzy set theory.

Petr Hájek

Arch. Math. Log., 2005

Logics for Data Mining.

Petr Hájek

Proceedings of the Data Mining and Knowledge Discovery Handbook., 2005

2004

Editorial.

Siegfried Gottwald, Petr Hájek

Fuzzy Sets Syst., 2004

The GUHA Method, Data Preprocessing and Mining.

Petr Hájek, Jan Rauch, David Coufal, Thomas Feglar

Proceedings of the Database Support for Data Mining Applications: Discovering Knowledge with Inductive Queries, 2004

A True Unprovable Formula of Fuzzy Predicate Logic.

Petr Hájek

Proceedings of the Logic versus Approximation, 2004

2003

Formal logics of discovery and hypothesis formation by machine.

Petr Hájek, Martin Holena

Theor. Comput. Sci., 2003

Observations on non-commutative fuzzy logic.

Petr Hájek

Soft Comput., 2003

Basic fuzzy logic and BL-algebras II.

Petr Hájek

Soft Comput., 2003

Fuzzy Logics with Noncommutative Conjuctions.

Petr Hájek

J. Log. Comput., 2003

Hoops and Fuzzy Logic.

Francesc Esteva, Lluís Godo, Petr Hájek, Franco Montagna

J. Log. Comput., 2003

The sorites paradox and fuzzy logic.

Petr Hájek, Vilém Novák

Int. J. Gen. Syst., 2003

A Fuzzy Modal Logic for Belief Functions.

Lluís Godo, Petr Hájek, Francesc Esteva

Fundam. Informaticae, 2003

On generalized quantifiers, finite sets and data mining.

Petr Hájek

Proceedings of the Intelligent Information Processing and Web Mining, 2003

Fleas and fuzzy logic: a survey.

Petr Hájek

Proceedings of the 3rd Conference of the European Society for Fuzzy Logic and Technology, 2003

The GUHA Method and Foundations of (Relational) Data Mining.

Petr Hájek, Martin Holena, Jan Rauch

Proceedings of the Theory and Applications of Relational Structures as Knowledge Instruments, 2003

Relations and GUHA-Style Data Mining II.

Petr Hájek

Proceedings of the Relational and Kleene-Algebraic Methods in Computer Science: 7th International Seminar on Relational Methods in Computer Science and 2nd International Workshop on Applications of Kleene Algebra, 2003

2002

Monadic Fuzzy Predicate Logics.

Petr Hájek

Stud Logica, 2002

A New Small Emendation of Gödel's Ontological Proof.

Petr Hájek

Stud Logica, 2002

On Lukasiewicz's Four-Valued Modal Logic.

Josep Maria Font, Petr Hájek

Stud Logica, 2002

Observations on the monoidal t-norm logic.

Petr Hájek

Fuzzy Sets Syst., 2002

2001

Fuzzy Logic and Arithmetical Hierarchy III.

Petr Hájek

Stud Logica, 2001

Complexity of Fuzzy Probability Logics.

Petr Hájek, Sauro Tulipani

Fundam. Informaticae, 2001

Editorial.

Petr Hájek, Lluís Godo, Siegfried Gottwald

Fuzzy Sets Syst., 2001

On very true.

Petr Hájek

Fuzzy Sets Syst., 2001

A note on the notion of truth in fuzzy logic.

Petr Hájek, John C. Shepherdson

Ann. Pure Appl. Log., 2001

Complexity of t-tautologies.

Matthias Baaz, Petr Hájek, Franco Montagna, Helmut Veith

Ann. Pure Appl. Log., 2001

A Set Theory within Fuzzy Logic.

Petr Hájek, Zuzana Haniková

Proceedings of the 31st IEEE International Symposium on Multiple-Valued Logic, 2001

Relations in GUHA Style Data Mining.

Petr Hájek

Proceedings of the Relational Methods in Computer Science, 2001

2000

Rational Pavelka Predicate Logic Is A Conservative Extension of Lukasiewicz Predicate Logic.

Petr Hájek, Jeff B. Paris, John C. Shepherdson

J. Symb. Log., 2000

The Liar Paradox and Fuzzy Logic.

Petr Hájek, Jeff B. Paris, John C. Shepherdson

J. Symb. Log., 2000

Knowledge-Driven versus Data-Driven Logics.

Didier Dubois, Petr Hájek, Henri Prade

J. Log. Lang. Inf., 2000

A Hedge for Gödel Fuzzy Logic.

Petr Hájek, Dagmar Harmancová

Int. J. Uncertain. Fuzziness Knowl. Based Syst., 2000

Residuated fuzzy logics with an involutive negation.

Francesc Esteva, Lluís Godo, Petr Hájek, Mirko Navara

Arch. Math. Log., 2000

1999

Fuzzy inference as deduction.

Lluís Godo, Petr Hájek

J. Appl. Non Class. Logics, 1999

Ten Questions and One Problem on Fuzzy Logic.

Petr Hájek

Ann. Pure Appl. Log., 1999

Logics and Statistics for Association Rules and Beyond Abstract of Tutorial.

Petr Hájek, Jan Rauch

Proceedings of the Principles of Data Mining and Knowledge Discovery, 1999

1998

Basic fuzzy logic and BL-algebras.

Petr Hájek

Soft Comput., 1998

Ten claims about fuzzy logic.

Petr Hájek

Soft Comput., 1998

Embedding Logics into Product Logic.

Matthias Baaz, Petr Hájek, David Svejda, Jan Krajícek

Stud Logica, 1998

Trakhtenbrot Theorem and Fuzzy Logic.

Petr Hájek

Proceedings of the Computer Science Logic, 12th International Workshop, 1998

Metamathematics of Fuzzy Logic

Petr Hájek

Trends in Logic 4, Kluwer, ISBN: 978-94-011-5300-3, 1998

1997

A dialogue on fuzzy logic.

Petr Hájek, Jeff B. Paris

Soft Comput., 1997

Fuzzy Logic and Arithmetical Hierarchy, II.

Petr Hájek

Stud Logica, 1997

CADIAG-2 and MYCIN-like systems.

Milan Daniel, Petr Hájek, Phuong Hoang Nguyen

Artif. Intell. Medicine, 1997

1996

Fuzzy Implications and generalized Quantifiers.

Petr Hájek, Ladislav J. Kohout

Int. J. Uncertain. Fuzziness Knowl. Based Syst., 1996

The Prague seminar of applied mathematical logic and its work on fuzzy logic.

Petr Hájek, Dagmar Harmancová

Fuzzy Sets Syst., 1996

A complete many-valued logic with product-conjunction.

Petr Hájek, Lluís Godo, Francesc Esteva

Arch. Math. Log., 1996

1995

A qualitative fuzzy possibilistic logic.

Petr Hájek, Dagmar Harmancová, Rineke Verbrugge

Int. J. Approx. Reason., 1995

Fuzzy logic and probability.

Petr Hájek, Lluís Godo, Francesc Esteva

Proceedings of the UAI '95: Proceedings of the Eleventh Annual Conference on Uncertainty in Artificial Intelligence, 1995

Fuzzy Logic From The Logical Point of View.

Petr Hájek

Proceedings of the SOFSEM '95, 22nd Seminar on Current Trends in Theory and Practice of Informatics, Milovy, Czech Republic, November 23, 1995

Medical Fuzz;y Expert Systems and Reasoning about Beliefs.

Petr Hájek, Dagmar Harmancová

Proceedings of the Artificial Intelligence Medicine, 1995

1994

Review of Leonard Bolc and Piotr Borowik: Many-valued Logics: 1. Theoretical Foundations.

Petr Hájek, Richard Zach

J. Appl. Non Class. Logics, 1994

A Qualitative Belief Logic.

David Harmanec, Petr Hájek

Int. J. Uncertain. Fuzziness Knowl. Based Syst., 1994

On Modal Logics for Qualitative Possibility in a Fuzzy Setting.

Petr Hájek, Dagmar Harmancová, Francesc Esteva, Pere Garcia, Lluís Godo

Proceedings of the UAI '94: Proceedings of the Tenth Annual Conference on Uncertainty in Artificial Intelligence, 1994

Possibilistic Logic as Interpretability Logic.

Petr Hájek

Proceedings of the Advances in Intelligent Computing, 1994

1993

Epistemic Entrenchment and Arithmetical Hierarchy.

Petr Hájek

Artif. Intell., 1993

A Comparative Fuzzy Modal Logic.

Petr Hájek, Dagmar Harmancová

Proceedings of the Fuzzy Logic in Artificial Intelligence, 1993

Epistemic Entrenchment and Arthmetical Hierarchy (Abstract).

Petr Hájek

Proceedings of the Computational Logic and Proof Theory, Third Kurt Gödel Colloquium, 1993

Metamathematics of First-Order Arithmetic.

Petr Hájek, Pavel Pudlák

Perspectives in mathematical logic, Springer, ISBN: 978-3-540-63648-9, 1993

1992

The logic of<i>II</i>₁-conservativity continued.

Petr Hájek, Franco Montagna

Arch. Math. Log., 1992

On Logics of Approximate Reasoning.

Petr Hájek

Proceedings of the Knowledge Representation and Reasoning Under Uncertainty, 1992

On Belief Functions.

Petr Hájek, David Harmanec

Proceedings of the Advanced Topics in Artificial Intelligence, 1992

Uncertain information processing in expert systems.

Petr Hájek, Tomás Havránek, Radim Jirousek

CRC Press, ISBN: 978-0-8493-6368-9, 1992

1991

A note on the normal form of closed formulas of interpretability logic.

Petr Hájek, Vítezslav Svejdar

Stud Logica, 1991

1990

The logic of π₁-conservativity.

Petr Hájek, Franco Montagna

Arch. Math. Log., 1990

On some formalized conservation results in arithmetic.

Peter Clote, Petr Hájek, Jeff B. Paris

Arch. Math. Log., 1990

1989

The expert system shell EQUANT-PC: brief information.

Petr Hájek, Marie Hájková, Tomás Havránek, Milan Daniel

Kybernetika, 1989

On Recursion Theory in I Sigma₁.

Petr Hájek, Antonín Kucera

J. Symb. Log., 1989

1987

Combinatorial principles concerning approximations of functions.

Petr Hájek, Jeff B. Paris

Arch. Math. Log., 1987

1986

A simple dynamic logic.

Petr Hájek

Theor. Comput. Sci., 1986

1985

Combining Functions for Certainty Degrees in Consulting Systems.

Petr Hájek

Int. J. Man Mach. Stud., 1985

1983

Arithmetical Interpretations of Dynamic Logic.

Petr Hájek

J. Symb. Log., 1983

1982

Applying Artificial Intelligence to Data Analysis.

Petr Hájek

Proceedings of the 5th European Conference on Artificial Intelligence, 1982

1981

Decision Problems of Some Statistically Motivated Monadic Modal Calculi.

Petr Hájek

Int. J. Man Mach. Stud., 1981

Introduction.

Petr Hájek

Int. J. Man Mach. Stud., 1981

A second-order dynamic logic with array assignments.

Petr Hájek, Petr Kurka

Fundam. Informaticae, 1981

Making Dynamic Logic First-Order.

Petr Hájek

Proceedings of the Mathematical Foundations of Computer Science 1981, Strbske Pleso, Czechoslovakia, August 31, 1981

1980

On dynamic logic.

Petr Hájek, Pavel Kalásek, Petr Kurka

Kybernetika, 1980

1979

Arithmetical Hierarchy and Complexity of Computation.

Petr Hájek

Theor. Comput. Sci., 1979

1978

On Sequences of Degrees of Constructibility (Solution of Friedman'S Problem 75).

Bohuslav Balcar, Petr Hájek

Math. Log. Q., 1978

1977

Experimental Logics and pi⁰₃ Theories.

Petr Hájek

J. Symb. Log., 1977

On Generation of Inductive Hypotheses.

Petr Hájek, Tomás Havránek

Int. J. Man Mach. Stud., 1977

Arithmetical Complexity of Some Problems in Computer Science.

Petr Hájek

Proceedings of the Mathematical Foundations of Computer Science 1977, 1977

1975

Observationsfunktorenkalküle und die Logik der automatisierten Forschung.

Petr Hájek

J. Inf. Process. Cybern., 1975

On Logics of Discovery.

Petr Hájek

Proceedings of the Mathematical Foundations of Computer Science 1975, 1975

1974

Automatic listing of important observational statements. III.

Petr Hájek

Kybernetika, 1974

1973

On generalized credence functions.

Petr Hájek, Dagmar Harmancová

Kybernetika, 1973

Automatic listing of important observational statements. II.

Petr Hájek

Kybernetika, 1973

Automatic listing of important observational statements. I.

Petr Hájek

Kybernetika, 1973

Some Logical Problems of Automated Research.

Petr Hájek

Proceedings of the Mathematical Foundations of Computer Science: Proceedings of Symposium and Summer School, 1973

1971

The GUHA method and the three-valued logic.

Petr Hájek, Kamila Bendová, Zdenek Renc

Kybernetika, 1971

1968

The problem of a general conception of the GUHA method.

Petr Hájek

Kybernetika, 1968

1967

The GUHA method of systematical hypotheses searching. II.

Petr Hájek, Ivan Havel, Metodej K. Chytil

Kybernetika, 1967

1966

GUHA - the method of systematical hypotheses searching.

Petr Hájek, Ivan Havel, Metodej K. Chytil

Kybernetika, 1966

The GUHA method of automatic hypotheses determination.

Petr Hájek, Ivan Havel, Metodej K. Chytil

Computing, 1966