A new approach to study the evolution complexity of cellular automata is proposed and explained thoroughly by an example of elementary cellular automaton of rule 56. Using the tools of distinct excluded blocks, comput...A new approach to study the evolution complexity of cellular automata is proposed and explained thoroughly by an example of elementary cellular automaton of rule 56. Using the tools of distinct excluded blocks, computational search and symbolic dynamics, the mathematical structure underlying the time series generated from the elementary cellular automaton of rule 56 is analyzed and its complexity is determined, in which the Dyck language and Catalan numbers emerge naturally.展开更多
This paper investigates the approach of presenting groups by generators and relations from an original angle. It starts by interpreting this familiar concept with the novel notion of “formal words” created by juxtap...This paper investigates the approach of presenting groups by generators and relations from an original angle. It starts by interpreting this familiar concept with the novel notion of “formal words” created by juxtaposing letters in a set. Taking that as basis, several fundamental results related to free groups, such as Dyck’s Theorem, are proven. Then, the paper highlights three creative applications of the concept in classifying finite groups of a fixed order, representing all dihedral groups geometrically, and analyzing knots topologically. All three applications are of considerable significance in their respective topic areas and serve to illustrate the advantages and certain limitations of the approach flexibly and comprehensively.展开更多
In this paper, we study the class S of skew Motzkin paths, i.e., of those lattice paths that are in the first quadrat, which begin at the origin, end on the x-axis, consist of up steps U =（1, 1）,down steps D =（1,-1...In this paper, we study the class S of skew Motzkin paths, i.e., of those lattice paths that are in the first quadrat, which begin at the origin, end on the x-axis, consist of up steps U =（1, 1）,down steps D =（1,-1）, horizontal steps H =（1, 0）, and left steps L =（-1,-1）, and such that up steps never overlap with left steps. Let S;be the set of all skew Motzkin paths of length n and let 8;= |S;|. Firstly we derive a counting formula, a recurrence and a convolution formula for sequence{8;}n≥0. Then we present several involutions on S;and consider the number of their fixed points.Finally we consider the enumeration of some statistics on S;.展开更多
基金Research supported by the National Natural Science Foundation of China(10771100)the Higher Schools Natural Science Basic Research Foundation of Jiangsu Province(06KJD110179)
基金the "973" Project on Mathematical Mechanizationthe National Science Foundation, the Ministry of Education, and the Ministry of Science and Technology of China.
基金This work is supported by the Special Funds for Major State Basic Research Project.
文摘A new approach to study the evolution complexity of cellular automata is proposed and explained thoroughly by an example of elementary cellular automaton of rule 56. Using the tools of distinct excluded blocks, computational search and symbolic dynamics, the mathematical structure underlying the time series generated from the elementary cellular automaton of rule 56 is analyzed and its complexity is determined, in which the Dyck language and Catalan numbers emerge naturally.
文摘This paper investigates the approach of presenting groups by generators and relations from an original angle. It starts by interpreting this familiar concept with the novel notion of “formal words” created by juxtaposing letters in a set. Taking that as basis, several fundamental results related to free groups, such as Dyck’s Theorem, are proven. Then, the paper highlights three creative applications of the concept in classifying finite groups of a fixed order, representing all dihedral groups geometrically, and analyzing knots topologically. All three applications are of considerable significance in their respective topic areas and serve to illustrate the advantages and certain limitations of the approach flexibly and comprehensively.
基金Supported by National Natural Science Foundation of China(Grant No.11571150)
文摘In this paper, we study the class S of skew Motzkin paths, i.e., of those lattice paths that are in the first quadrat, which begin at the origin, end on the x-axis, consist of up steps U =（1, 1）,down steps D =（1,-1）, horizontal steps H =（1, 0）, and left steps L =（-1,-1）, and such that up steps never overlap with left steps. Let S;be the set of all skew Motzkin paths of length n and let 8;= |S;|. Firstly we derive a counting formula, a recurrence and a convolution formula for sequence{8;}n≥0. Then we present several involutions on S;and consider the number of their fixed points.Finally we consider the enumeration of some statistics on S;.
