scholarly journals Linear-bounded composition of tree-walking tree transducers: linear size increase and complexity

2019 ◽  
Author(s):  
Joost Engelfriet ◽  
Kazuhiro Inaba ◽  
Sebastian Maneth
Keyword(s):  
Linear Size ◽  
Size Increase ◽  
Tree Transducers

scholarly journals A Survey on Decidable Equivalence Problems for Tree Transducers

2015 ◽  
Vol 26 (08) ◽  
pp. 1069-1100 ◽  
Author(s):  
Sebastian Maneth
Keyword(s):  
Open Problem ◽  
Linear Size ◽  
Size Increase ◽  
Top Down ◽  
Natural Restriction ◽  
Input And Output ◽  
Tree Transducers ◽  
Full Class ◽  
Equivalence Problems

The decidability of equivalence for three important classes of tree transducers is discussed. Each class can be obtained as a natural restriction of deterministic macro tree transducers (MTTs): (1) no context parameters, i.e., top-down tree transducers, (2) linear size increase, i.e., MSO definable tree transducers, and (3) monadic input and output ranked alphabets. For the full class of mtts, decidability of equivalence remains a long-standing open problem.

Macro Tree Translations of Linear Size Increase are MSO Definable

2003 ◽  
Vol 32 (4) ◽  
pp. 950-1006 ◽  
Author(s):  
Joost Engelfriet ◽  
Sebastian Maneth
Keyword(s):  
Linear Size ◽  
Size Increase

Improving the efficiency of hardening of tillage machine working bodies by arc surfacing using wear-resistant rollers

2020 ◽  
pp. 176-185
Author(s):  
Dmitriy B. Slinko ◽  
Vyacheslav A. Denisov ◽  
Dmitriy A. Dobrin ◽  
Andrey V. Afanas’yev ◽  
Pavel M. Kislov
Keyword(s):  
Wear Resistance ◽  
Operating Time ◽  
Field Tests ◽  
Electric Arc ◽  
Cutting Edge ◽  
Linear Size ◽  
Research Purpose ◽  
Cored Wire ◽  
Wear Resistant ◽  
Working Bodies

Reducing operating costs during soil processing and increasing the wear resistance of parts and components is an important condition for reducing the cost of agricultural products, increasing its efficiency and competitiveness. The development of materials with increased wear resistance and new effective technologies for strengthening working bodies in their manufacture is now becoming an urgent task. (Research purpose) The research purpose is increasing the wear resistance of the working bodies of soil-processing machines by electric arc surfacing. (Materials and methods) During the experimental study, it has been performed testing of modes and surfacing of a pilot batch of working bodies from Kverneland for field tests in VIM on an automated installation for electric arc surfacing. Authors used eutectic CastolinEnDotec DO*30 powder wire with a diameter of 1.2 millimeters and a boron content of up to 4 percent for surfacing wear-resistant rollers, which allows to obtain wear-resistant rollers with a hardness of up to 65 HRC without pores and cracks. (Results and discussion) It has been revealed that hardened ploughshares that have passed field tests are subject to lower wear rates compared to non-hardened ones. It was found that when operating time is 24.785 hectares per ploughshare, the wear of the linear size of the cutting edge along the width of hardened ploughshares is on average up to 10-11 millimeters less than that of non-hardened ones. It was found that when processing 228 hectares, the wear of the linear size of the cutting edge along the width of hardened bits is on average up to 9-10 millimeters less than that of non-hardened ones. (Conclusions) The technology of surfacing with intermittent wear-resistant rollers provides an increase in the efficiency of hardening of Kverneland working bodies according to the criterion of wear resistance by an average of 20-30 percent. The adjusted technological parameters of the surfacing process will reduce the wear rate and increase the service life of the blade part of the working bodies, as well as reduce the amount of surfaced material by an average of 60 percent. The continuation of work on strengthening the working bodies should be aimed at changing the surfacing scheme and choosing a cheaper domestic cored wire.

Tree Rewriting Systems, Combinatory Weak Reduction Systems and Type Free Languages1

1982 ◽  
Vol 5 (3-4) ◽  
pp. 279-299
Author(s):  
Alberto Pettorossi
Keyword(s):  
Combinatory Logic ◽  
Rewriting Systems ◽  
Tree Transducers ◽  
Tree Languages ◽  
One To One ◽  
The One ◽  
Weak Reduction

In this paper we consider combinators as tree transducers: this approach is based on the one-to-one correspondence between terms of Combinatory Logic and trees, and on the fact that combinators may be considered as transformers of terms. Since combinators are terms themselves, we will deal with trees as objects to be transformed and tree transformers as well. Methods for defining and studying tree rewriting systems inside Combinatory Weak Reduction Systems and Weak Combinatory Logic are also analyzed and particular attention is devoted to the problem of finiteness and infinity of the generated tree languages (here defined). This implies the study of the termination of the rewriting process (i.e. reduction) for combinators.

Higher-order multi-parameter tree transducers and recursion schemes for program verification

2010 ◽  
Vol 45 (1) ◽  
pp. 495-508 ◽  
Author(s):  
Naoki Kobayashi ◽  
Naoshi Tabuchi ◽  
Hiroshi Unno
Keyword(s):  
Program Verification ◽  
Higher Order ◽  
Tree Transducers

PROPERTIES OF QUASI-RELABELING TREE BIMORPHISMS

2010 ◽  
Vol 21 (03) ◽  
pp. 257-276 ◽  
Author(s):  
ANDREAS MALETTI ◽  
CĂTĂLIN IONUŢ TÎRNĂUCĂ
Keyword(s):  
Cartesian Product ◽  
Canonical Representation ◽  
Finite Union ◽  
Top Down ◽  
Tree Language ◽  
Regular Tree ◽  
Fundamental Properties ◽  
Tree Transducers ◽  
Tree Languages ◽  
Context Free

The fundamental properties of the class QUASI of quasi-relabeling relations are investigated. A quasi-relabeling relation is a tree relation that is defined by a tree bimorphism (φ, L, ψ), where φ and ψ are quasi-relabeling tree homomorphisms and L is a regular tree language. Such relations admit a canonical representation, which immediately also yields that QUASI is closed under finite union. However, QUASI is not closed under intersection and complement. In addition, many standard relations on trees (e.g., branches, subtrees, v-product, v-quotient, and f-top-catenation) are not quasi-relabeling relations. If quasi-relabeling relations are considered as string relations (by taking the yields of the trees), then every Cartesian product of two context-free string languages is a quasi-relabeling relation. Finally, the connections between quasi-relabeling relations, alphabetic relations, and classes of tree relations defined by several types of top-down tree transducers are presented. These connections yield that quasi-relabeling relations preserve the regular and algebraic tree languages.

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