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14
A comparison of pebble tree transducers with macro tree transducers
 Acta Informatica
, 2003
"... Abstract. The npebble tree transducer was recently proposed as a model for XML query languages. The four main results on deterministic transducers are: First, (1) the translation τ of an npebble tree transducer can be realized by a composition of n + 1 0pebble tree transducers. Next, the pebble t ..."
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Cited by 37 (10 self)
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Abstract. The npebble tree transducer was recently proposed as a model for XML query languages. The four main results on deterministic transducers are: First, (1) the translation τ of an npebble tree transducer can be realized by a composition of n + 1 0pebble tree transducers. Next, the pebble tree transducer is compared with the macro tree transducer, a wellknown model for syntaxdirected semantics, with decidable type checking. The 0pebble tree transducer can be simulated by the macro tree transducer, which, by the first result, implies that (2) τ can be realized by an (n+1)fold composition of macro tree transducers. Conversely, every macro tree transducer can be simulated by a composition of 0pebble tree transducers. Together these simulations prove that (3) the composition closure of npebble tree transducers equals that of macro tree transducers (and that of 0pebble tree transducers). Similar results hold in the nondeterministic case. Finally, (4) the output languages of deterministic npebble tree transducers form a hierarchy with respect to the number n of pebbles. 1
S.: The equivalence problem for deterministic MSO tree transducers is decidable
 Inf. Process. Lett
, 2006
"... Abstract. It is decidable for deterministic MSO definable graphtostring or graphtotree transducers whether they are equivalent on a contextfree set of graphs. It is well known that the equivalence problem for nondeterministic (oneway) finite state transducers is undecidable, even when they cann ..."
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Cited by 8 (1 self)
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Abstract. It is decidable for deterministic MSO definable graphtostring or graphtotree transducers whether they are equivalent on a contextfree set of graphs. It is well known that the equivalence problem for nondeterministic (oneway) finite state transducers is undecidable, even when they cannot read or write the empty string [Gri68]. In contrast, equivalence is decidable for deterministic finite state transducers, even for twoway transducers [Gur82]. The question arises whether these results can be generalized from strings to transducers working on more complex structures like, e.g., trees or graphs. There is no accepted notion of finite state transducer working on graphs; instead, it is believed that transductions expressed in monadic secondorder logic (MSO) are the natural counterpart of finite state transductions on graphs. The idea is to define an output graph by interpreting fixed MSO formulas on a given input graph. In fact, if the input and output graphs of such an MSO graph transducer are strings, then the resulting transductions (in the deterministic case) are precisely the deterministic twoway finite state transductions [EH01]. Hence, by the above, equivalence is decidable for deterministic MSO string transducers. A nondeterministic MSO graph
The Complexity of Translation Membership for Macro Tree Transducers
"... Macro tree transducers (mtts) are a useful formal model for XML query and transformation languages. In this paper one of the fundamental decision problems on translations, namely the “translation membership problem ” is studied for mtts. For a fixed translation, the translation membership problem as ..."
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Cited by 2 (0 self)
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Macro tree transducers (mtts) are a useful formal model for XML query and transformation languages. In this paper one of the fundamental decision problems on translations, namely the “translation membership problem ” is studied for mtts. For a fixed translation, the translation membership problem asks whether a given input/output pair is element of the translation. For callbyname mtts this problem is shown to be NPcomplete. The main result is that translation membership for callbyvalue mtts is in polynomial time. For several extensions, such as addition of regular lookahead or the generalization to multireturn mtts, it is shown that translation membership still remains in PTIME. 1.
Millstream systems
"... We introduce Millstream systems, a mathematical framework in the tradition of the Theory of Computation that uses logic to formalize the interfaces between different aspects of language, the latter being described by any number of independent modules. Unlike other approaches that serve a similar goa ..."
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Cited by 2 (2 self)
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We introduce Millstream systems, a mathematical framework in the tradition of the Theory of Computation that uses logic to formalize the interfaces between different aspects of language, the latter being described by any number of independent modules. Unlike other approaches that serve a similar goal, Millstream systems neither presuppose nor establish a particular linguistic theory or focus, but can be instantiated in various ways to accomodate different points of view. UMINF 09.21 Copyright c ○ 2009 ISSN 03480542 1
Tree transformations and dependencies
"... Abstract. Several tree transformation devices that are relevant in natural language processing are presented with a focus on the dependencies that they are able to capture. In many cases, the consideration of the dependencies alone can be used to provide a highlevel explanation of the shortcomings ..."
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Cited by 1 (1 self)
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Abstract. Several tree transformation devices that are relevant in natural language processing are presented with a focus on the dependencies that they are able to capture. In many cases, the consideration of the dependencies alone can be used to provide a highlevel explanation of the shortcomings of tree transformation devices and allows surprising insights into their structure. 1
Tree Transducers and Their Applications to XML
"... The present document contains notes on a course held in Tarragona/Spain at the ..."
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The present document contains notes on a course held in Tarragona/Spain at the
Finitary Compositions of Twoway FiniteState Transductions
, 2007
"... The hierarchy of arbitrary compositions of twoway nondeterministic finitestate transductions collapses when restricted to finitary transductions, i.e., transductions that produce a finite set of outputs for each input. The hierarchy collapses to the class of nondeterministic MSO definable transdu ..."
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The hierarchy of arbitrary compositions of twoway nondeterministic finitestate transductions collapses when restricted to finitary transductions, i.e., transductions that produce a finite set of outputs for each input. The hierarchy collapses to the class of nondeterministic MSO definable transductions, which is inside the second level of that hierarchy. It is decidable whether a composition of twoway nondeterministic finitestate transducers realizes a finitary transduction (i.e., is MSO definable).
PolynomialTime Inverse Computation for Accumulative Functions with Multiple Data Traversals
"... Inverse computation has many applications such as serialization/deserialization, providing support for undo, and testcase generation for software testing. In this paper, we propose an inverse computation method that always terminates for a class of functions known as parameterlinear macro tree tra ..."
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Inverse computation has many applications such as serialization/deserialization, providing support for undo, and testcase generation for software testing. In this paper, we propose an inverse computation method that always terminates for a class of functions known as parameterlinear macro tree transducers, which involve multiple data traversals and the use of accumulations. The key to our method is the observation that a function in the class can be regarded as a nonaccumulative contextgenerating transformation without multiple data traversals. Accordingly, we demonstrate that it is easy to achieve terminating inverse computation for the class by contextwise memoization of the inverse computation results. We also show that when we use a tree automaton to express the inverse computation results, the inverse computation runs in time polynomial to the size of the original output and the textual program size.
Author manuscript, published in "35th International Symposium on Mathematical Foundations of Computer Science (2010) xxx" Properties of Visibly Pushdown Transducers ⋆
, 2010
"... Abstract. Visibly pushdown transducers (VPTs) form a strict subclass of pushdown transducers (PTs) that extends finite state transducers with a stack. Like visibly pushdown automata, the input symbols determine the stack operations. It has been shown that visibly pushdown languages form a robust sub ..."
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Abstract. Visibly pushdown transducers (VPTs) form a strict subclass of pushdown transducers (PTs) that extends finite state transducers with a stack. Like visibly pushdown automata, the input symbols determine the stack operations. It has been shown that visibly pushdown languages form a robust subclass of contextfree languages. Along the same line, we show that word transductions defined by VPTs enjoy strong properties, in contrast to PTs. In particular, functionality is decidable in PTIME, kvaluedness is in NPTIME and equivalence of (nondeterministic) functional VPTs is EXPTIMEC. Those problems are undecidable for PTs. Output words of VPTs are not necessarily wellnested. We identify a general subclass of VPTs that produce wellnested words, which is closed by composition, and for which the type checking problem is decidable. 1