Reaction Automata Working in Sequential Manner
Reaction Automata Working in Sequential Manner
复制标题
以顺序方式工作的反应自动机
DOI:
10.1051/ita/2013047
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发表时间:
2014
期刊:
影响因子:
--
通讯作者:
Fumiya Okubo
中科院分区:
文献类型:
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作者:
Fumiya Okubo
In recent years, Ehrenfeucht and Rozenberg have introduced a formal model, called reaction systems [5], for investigating the functioning of the living cell, based on the idea that the functioning is decided by interactions between biochemical reactions, where two basic components (reactants and inhibitors) play a key role as a regulation mechanism in controlling interactions. In [6], it is shown that reaction systems provide a formal framework suited for investigating in an abstract level the way of emergence and evolution of biochemical events and modules. Recent papers continue the investigation of reaction systems in various topics motivated by biological and theoretical considerations, such as the issue of times for creating compounds [7], combinatorial properties of functions defined by reaction systems [8, 9, 18], probabilistic and quantum variants of reaction systems [11]. In the theory of reaction systems, a biochemical reaction is formulated as a triple a=(Ra, Ia, Pa), where Ra is the set of molecules called reactants, Ia is the set of molecules called inhibitors, and Pa is the set of molecules called products. Let T be a set of molecules, and the result of applying a reaction a to T, denoted by resa (T), is given by Pa if a is enabled by T (ie, if Ra is included in T and Ia is disjoint with T). Otherwise, the result is empty. Thus, resa (T)= Pa if a is enabled on T, and resa (T)=∅ otherwise. The result of applying a reaction a is extended to the set of reactions A, denoted by resA (T), and an interactive process consisting of a sequence of resA (T)’s is properly introduced and investigated. Inspired by the notion of reaction systems, reaction automata have been introduced in [15] as computing devices, and it has been shown that they are computationally universal by proving that all recursively enumerable languages are accepted by reaction automata. In [16], the investigation with reaction automata is continued with a focus on the formal language theoretic properties of spacebounded classes of reaction automata. Specifically, it is shown that all contextsensitive languages are accepted by exponential space bounded reaction automata. The notion of reaction automata may be regarded as an extension of reaction systems in the sense that reactants and inhibitors are employed as regulation in reaction automata, however they deal with multisets rather than usual sets as reaction systems do. Reaction automata are introduced as multiset rewriting devices that accept languages over an alphabet, where this feature is realized by a simple idea of feeding one symbol of an input string at each step of computation, to the device from the environment. In this sense, reaction automata may also be regarded as simplified variants of P automata introduced by Csuhaj− Varjú and Vaszil in [4] with no membrane structure.In this paper, we continue the investigation of reaction automata with a focus on the way of rule application. We consider not only maximally parallel manner employed in [15, 16], but also sequential manner as the way of rule application, and compare the computational powers of reaction automata and their spacebounded variants in the above two manners. Reaction automata with λ-moves (introduced in [16]) in sequential manner are also investigated. Further, we explore a