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  1.  10
    Elements of the Theory of Computation.Harry R. Lewis & Christos H. Papadimitriou - 1984 - Journal of Symbolic Logic 49 (3):989-990.
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  2.  16
    Unsolvable Classes of Quantificational Formulas.Harry R. Lewis - 1979 - Addison-Wesley.
  3. Linear Sampling and the ∀∃∀ Case of the Decision Problem.Stal O. Aanderaa & Harry R. Lewis - 1974 - Journal of Symbolic Logic 39 (3):519-548.
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  4.  21
    The Word Problem for Cancellation Semigroups with Zero.Yuri Gurevich & Harry R. Lewis - 1984 - Journal of Symbolic Logic 49 (1):184-191.
    By theword problemfor some class of algebraic structures we mean the problem of determining, given a finite setEof equations between words and an additional equationx=y, whetherx=ymust hold in all structures satisfying each member ofE. In 1947 Post [P] showed the word problem for semigroups to be undecidable. This result was strengthened in 1950 by Turing, who showed the word problem to be undecidable forcancellation semigroups,i.e. semigroups satisfying thecancellation propertyNovikov [N] eventually showed the word problem for groups to be undecidable.In 1966 (...)
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  5.  30
    The Decision Problem for Formulas with a Small Number of Atomic Subformulas.Harry R. Lewis & Warren D. Goldfarb - 1973 - Journal of Symbolic Logic 38 (3):471-480.
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  6.  47
    Conservative Reduction Classes of Krom Formulas.Stål O. Aanderaa, Egon Börger & Harry R. Lewis - 1982 - Journal of Symbolic Logic 47 (1):110-130.
    A Krom formula of pure quantification theory is a formula in conjunctive normal form such that each conjunct is a disjunction of at most two atomic formulas or negations of atomic formulas. Every class of Krom formulas that is determined by the form of their quantifier prefixes and which is known to have an unsolvable decision problem for satisfiability is here shown to be a conservative reduction class. Therefore both the general satisfiability problem, and the problem of satisfiability in finite (...)
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  7.  28
    Prefix Classes of Krom Formulas.Stål O. Aanderaa & Harry R. Lewis - 1973 - Journal of Symbolic Logic 38 (4):628-642.
  8.  27
    Skolem Reduction Classes.Warren D. Goldfarb & Harry R. Lewis - 1975 - Journal of Symbolic Logic 40 (1):62-68.
  9. Elements of the Theory of Computation Harry R. Lewis, Christos H. Papadimitriou.Harry R. Lewis & Christos H. Papadimitriou - 1998
     
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  10.  32
    Krom Formulas with One Dyadic Predicate Letter.Harry R. Lewis - 1976 - Journal of Symbolic Logic 41 (2):341-362.
  11.  24
    ΠGarey Michael R. And Johnson David S.. Computers and Intractability. A Guide to the Theory of NP-Completeness. W. H. Freeman and Company, San Francisco 1979, X + 338 Pp. [REVIEW]Harry R. Lewis - 1983 - Journal of Symbolic Logic 48 (2):498-500.
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  12. Review: Michael R. Garey, David S. Johnson, Computers and Intractability. A Guide to the Theory of NP-Completeness. [REVIEW]Harry R. Lewis - 1983 - Journal of Symbolic Logic 48 (2):498-500.