tailieunhanh - Báo cáo toán học: "The subword complexity of a two-parameter family of sequences"

Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí toán học quốc tế đề tài: The subword complexity of a two-parameter family of sequences. | The subword complexity of a two-parameter family of sequences Aviezri S. Fraenkel Tamar Seeman Department of Computer Science and Applied Mathematics The Weizmann Institute of Science Rehovot 76100 Israel fraenkel tamars@ http fraenkel tamars Jamie Simpson School of Mathematics Curtin University Perth WA 6001 Australia simpson@ http s impson RECEIVED 4 14 2000 ACCEPTED 2 06 2001 Abstract We determine the subword complexity of the characteristic functions of a two-parameter family I An y 1 of infinite sequences which are associated with the winning strategies for a family of 2-player games. A special case of the family has the form An _naj for all n e z 0 where a is a fixed positive irrational number. The characteristic functions of such sequences have been shown to have subword complexity n 1. We show that every sequence in the extended family has subword complexity O n . 1 Introduction Denote by z 0 and z 0 the set of nonnegative integers and positive integers respectively. Given two heaps of finitely many tokens we define a 2-player heap game as follows. There are two types of moves THE ELECTRONIC JOURNAL OF COMBINATORICS 8 no. 2 2001 R10 1 1. Remove any positive number of tokens from a single heap. 2. Remove k 0 tokens from one heap and l 0 from the other. Here k and l are constrained by the condition 0 k l sk t where s and t are predetermined positive integers. The player who reaches a state where both heaps are empty wins. The special case s t 1 is the classical Wythoff game 15 16 5 . Fraenkel showed 11 that every possible position in a game of this type can be classified as either a F-position in which the Previous player can win or an -position in which the Next player can win. Thus a winning strategy involves moving from an -position to a F-position. Let P denote the set of all possible F-positions in a game with given values for s and t. Let mex S denote the least .