Báo cáo toán học: "There are ternary circular square-free words of length n for n ≥ 18" doc

... squarefree word, i.e. an infinite sequence not containing any squares. Variations on the problem of finding squarefree words have included finding infinite squarefree tilings [2], or finding infinite ... There are ternary circular square-free words of length n for n ≥ 18. James D. Currie ∗ Department of Mathematics and Statistics University of Winnipeg Winnipeg, Mani...

Ngày tải lên: 07/08/2014, 06:23

... long binary circular words avoiding 2+ powers, but only for lengths of the form 2 m or 3 × 2 m . It was recently shown [1] that there are ternary square-free circular words of length n for n ≥ ... Let k ≥ 2 be a positive integer. Then t contains subwords of length k of the form 0v1 and of the form 0v0. Proof: Suppose that t has no subword 0v1oflengt...

Ngày tải lên: 07/08/2014, 08:20

... experimentation that went into formulation of a conjecture about the necessary and sufficient condition. We then will prove that the conjecture is true, using the method of generating functions. Then ... bijective proofofthefactthat (n, t, m) is uniform when the conditions of the theorem hold. The following recurrence was used in our computations. For nonnegative integers (n, t, m), an...

Ngày tải lên: 07/08/2014, 06:20

... enumerations of square-free ternary words of length n ≤ 110 [12] and on constructions of generalised Brinkhuis triples [11, 12]. 2 Ternary square-free words Denote the number of ternary square-free ... exist infinite ternary square-free words, i.e., square-free words on a three-letter alphabet. In fact, the number s n of ternary square-free words...

Ngày tải lên: 07/08/2014, 08:20

... choosable. Recently, the questions stated in Problems 1 and 2 were studied by Bartnicki, Grytczuk, and Niwczyk [BGN09]. Using a method relying on permanents of matrices and Combi- natorial Nullstellensatz, ... 1, which is one more than the number of colours guaranteed by Brooks’ Theorem in the case of non-complete graphs which are not odd cycles and precisely the chromatic number if G...

Ngày tải lên: 08/08/2014, 12:23

... 1 Department of Electronic Materials Engineering, Kwangwoon University, 447-1 Wolgye-dong, Nowon-gu, Seoul, 139-701, South Korea 2 Department of Mathematics and Information, Kyungwon Campus, Gachon University, ... inhomogeneities and Fermi- level pinning on Schottky contact properties has been known to be minimal, and the barrier height depends mostly on the metal work function witho...

Ngày tải lên: 20/06/2014, 20:20

... was 7 Integrated acoustic echo and background noise suppression technique based on soft decision Yun-Sik Park 1 and Joon-Hyuk Chang ∗2 1 School of Electronic Engineering, Inha University, Incheon ... in determining and modifying the suppres- sion gain based on soft decision. This is clearly different from the conventional integrated strategies requiring the AEC and NR independently. For th...

Ngày tải lên: 20/06/2014, 20:20

... (2a-c). N N N Cl CO 2 Et N N N N CO 2 Et H R N N N N H CO 2 H R N N N N CO 2 Et H N H 3 C N N N N H N CO 2 H H 3 C N N N N Cl N N N N N Cl H 3 C R N N NH 2 N N N CO 2 Et H R = H, OCH 3 , CH 3 , F, Cl, Br, NO 2 EtO 2 C Scheme ... prodrugs of phosphonoformate are potent in vitro inhibitors of nucleoside-resistant human immunodeficiency virus type...

Ngày tải lên: 20/06/2014, 20:20

... coding). Most studies on joint source/channel coding address the problem from an information theoretic point of view, and did not account for network performance and protocol issues, including ... Journal on Wireless Communications and Networking 2011, 2011:199 http://jwcn.eurasipjournals.com/content/2011/1/199 Page 17 of 17 this figure, variations of the channel condition are repre...

Ngày tải lên: 20/06/2014, 21:20

... BER performance in AWGN channels 3.1 BER performance of GFSK in AWGN channels In Figure 3, Z 1 and Z 2 are the outputs of conventional energy detectors, and they are defined as chi-square variables ... Thirumalaivasan, R Nakkeeran, UWB bandpass filter with notched band for the rejection of 5 GHz WLAN using hexagonal multiple mode resonator. in IEEE International Conference on Comm...

Ngày tải lên: 20/06/2014, 21:20