TY - GEN
T1 - Computational complexity studies of synchronous boolean finite dynamical systems
AU - Ogihara, Mitsunori
AU - Uchizawa, Kei
PY - 2015
Y1 - 2015
N2 - The finite dynamical system is a system consisting of some finite number of objects that take upon a value from some domain as a state, in which after initialization the states of the objects are updated based upon the states of the other objects and themselves according to a certain update schedule. This paper studies the subclass of finite dynamical systems the synchronous boolean finite dynamical system (synchronous BFDS, for short), where the states are boolean and the state update takes place in discrete time and at the same on all objects. The present paper is concerned with some problems regarding the behavior of synchronous BFDS in which the state update functions (or the local state transition functions) are chosen from a predetermined finite basis of boolean functions B. Specifically the following three behaviors are studied: - Convergence. Does a system at hand converge on a given initial state configuration? - Path Intersection. Will a system starting in given two state configurations produce a common configuration? - Cycle Length. Since the state space is finite, every BFDS on a given initial state configuration either converges or enters a cycle having length greater than 1. If the latter is the case, what is the length of the loop? Or put more simply, for an integer t, is the length of loop greater than t? The paper studies these questions in terms of computational complexity (in the case of Cycle Length using the decision version of the problem) and shows the following: 1. The three problems are each PSPACE-complete if the boolean function basis contains NAND, NOR or both AND and OR. 2. The Convergence Problem is solvable in polynomial time if the set B is one of {AND}, {OR} and {XOR,NXOR}. 3. If the set B is chosen from the three sets as in the case of the Convergence Problem, the Path Intersection Problem is in UP, and the Cycle Length Problem is in UP∩coUP; thus, these are unlikely to be NP-hard.
AB - The finite dynamical system is a system consisting of some finite number of objects that take upon a value from some domain as a state, in which after initialization the states of the objects are updated based upon the states of the other objects and themselves according to a certain update schedule. This paper studies the subclass of finite dynamical systems the synchronous boolean finite dynamical system (synchronous BFDS, for short), where the states are boolean and the state update takes place in discrete time and at the same on all objects. The present paper is concerned with some problems regarding the behavior of synchronous BFDS in which the state update functions (or the local state transition functions) are chosen from a predetermined finite basis of boolean functions B. Specifically the following three behaviors are studied: - Convergence. Does a system at hand converge on a given initial state configuration? - Path Intersection. Will a system starting in given two state configurations produce a common configuration? - Cycle Length. Since the state space is finite, every BFDS on a given initial state configuration either converges or enters a cycle having length greater than 1. If the latter is the case, what is the length of the loop? Or put more simply, for an integer t, is the length of loop greater than t? The paper studies these questions in terms of computational complexity (in the case of Cycle Length using the decision version of the problem) and shows the following: 1. The three problems are each PSPACE-complete if the boolean function basis contains NAND, NOR or both AND and OR. 2. The Convergence Problem is solvable in polynomial time if the set B is one of {AND}, {OR} and {XOR,NXOR}. 3. If the set B is chosen from the three sets as in the case of the Convergence Problem, the Path Intersection Problem is in UP, and the Cycle Length Problem is in UP∩coUP; thus, these are unlikely to be NP-hard.
UR - http://www.scopus.com/inward/record.url?scp=84929620665&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84929620665&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-17142-5_9
DO - 10.1007/978-3-319-17142-5_9
M3 - Conference contribution
AN - SCOPUS:84929620665
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 87
EP - 98
BT - Theory and Applications of Models of Computation - 12th Annual Conference, TAMC 2015, Proceedings
A2 - Jain, Rahul
A2 - Jain, Sanjay
A2 - Stephan, Frank
PB - Springer Verlag
T2 - 12th Annual Conference on Theory and Applications of Models of Computation, TAMC 2015
Y2 - 18 May 2015 through 20 May 2015
ER -