Completion for Logically Constrained Rewriting

We propose an abstract completion procedure for logically constrained term rewrite systems (LCTRSs). This procedure can be instantiated to both standard Knuth-Bendix completion and ordered completion for LCTRSs, and we present a succinct and uniform correctness proof. A prototype implementation illustrates the viability of the new completion approach

Constrained completion: Theory, implementation, and results

The Knuth-Bendix completion procedure produces complete sets of reductions but can not handle certain rewrite rules such as commutativity. In order to handle such theories, completion procedure were created to find complete sets of reductions modulo an equational theory. The major problem with this method is that it requires a specialized unification algorithm for the equational theory. Although this method works well when such an algorithm exists, these algorithms are not always available and thus alternative methods are needed to attack problems. A way of doing this is to use a completion procedure which finds complete sets of constrained reductions. This type of completion procedure neither requires specialized unification algorithms nor will it fail due to unorientable identities. We present a look at complete sets of reductions with constraints, developed by Gerald Peterson, and the implementation of such a completion procedure for use with HIPER - a fast completion system. The completion procedure code is given and shown correct along with the various support procedures which are needed by the constrained system. These support procedures include a procedure to find constraints using the lexicographic path ordering and a normal form procedure for constraints. The procedure has been implemented for use under the fast HIPER system, developed by Jim Christian, and thus is quick. We apply this new system, HIPER- extension, to attack a variety of word problems. Implementation alternatives are discussed, developed, and compared with each other as well as with the HIPER system. Finally, we look at the problem of finding a complete set of reductions for a ternary boolean algebra. Given are alternatives to attacking this problem and the already known solution along with its run in the HIPER-extension system --Abstract, page iii

Verifying procedural programs via constrained rewriting induction

This paper aims to develop a verification method for procedural programs via a transformation into Logically Constrained Term Rewriting Systems (LCTRSs). To this end, we extend transformation methods based on integer TRSs to handle arbitrary data types, global variables, function calls and arrays, as well as encode safety checks. Then we adapt existing rewriting induction methods to LCTRSs and propose a simple yet effective method to generalize equations. We show that we can automatically verify memory safety and prove correctness of realistic functions. Our approach proves equivalence between two implementations, so in contrast to other works, we do not require an explicit specification in a separate specification language

A theory of resolution

We review the fundamental resolution-based methods for first-order theorem proving and present them in a uniform framework. We show that these calculi can be viewed as specializations of non-clausal resolution with simplification. Simplification techniques are justified with the help of a rather general notion of redundancy for inferences. As simplification and other techniques for the elimination of redundancy are indispensable for an acceptable behaviour of any practical theorem prover this work is the first uniform treatment of resolution-like techniques in which the avoidance of redundant computations attains the attention it deserves. In many cases our presentation of a resolution method will indicate new ways of how to improve the method over what was known previously. We also give answers to several open problems in the area

Network Rewriting II: Bi- and Hopf Algebras

Bialgebras and their specialisation Hopf algebras are algebraic structures that challenge traditional mathematical notation, in that they sport two core operations that defy the basic functional paradigm of taking zero or more operands as input and producing one result as output. On the other hand, these peculiarities do not prevent studying them using rewriting techniques, if one works within an appropriate network formalism rather than the traditional term formalism. This paper restates the traditional axioms as rewriting systems, demonstrating confluence in the case of bialgebras and finding the (infinite) completion in the case of Hopf algebras. A noteworthy minor problem solved along the way is that of constructing a quasi-order with respect to which the rules are compatible

The first-order theory of lexicographic path orderings is undecidable

We show, under some assumption on the signature, that the *This formula not viewable on a Text-Browser* fragment of the theory of any lexicographic path ordering is undecidable. This applies to partial and to total precedences. Our result implies in particular that the simplification rule of ordered completion is undecidable

The ontology and literary status of the screenplay: the case of "Scriptfic"

Are screenplays - or at least some screenplays - works of literature? Until relatively recently, very few theorists had addressed this question. Thanks to recent work by scholars such as Ian W. Macdonald, Steven Maras, and Steven Price, theorizing the nature of the screenplay is back on the agenda after years of neglect (albeit with a few important exceptions) by film studies and literary studies (Macdonald 2004; Maras 2009; Price 2010). What has emerged from this work, however, is a general acceptance that the screenplay is ontologically peculiar and, as a result, a divergence of opinion about whether or not it is the kind of thing that can be literature.Specifically, recent discussion about the nature of the screenplay has tended to emphasize its putative lack of ontological autonomy from the film, its supposed inherent incompleteness, or both (Carroll 2008, 68-69; Maras 2009, 48; Price 2010, 38-42). Moreover, these sorts of claims about the screenplay's ontology - its essential nature - are often hitched to broader arguments. According to one such argument, a screenplay's supposed ontological tie to the production of a film is said to vitiate the possibility of it being a work of literature in its own right (Carroll 2008, 68-69; Maras 2009, 48). According to another, the screenplay's tenuous literary status is putatively explained by the idea that it is perpetually unfinished, akin to a Barthesian >> writerly text > Yes > Yes > No > scriptfic > scriptfic > scriptfic Scriptfics > series > virtual series air