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Note on Ward-Horadam H (X)-Binomials' Recurrences And
Note on Ward-Horadam H(x)- binomials' recurrences and related interpretations, II Andrzej Krzysztof Kwa´sniewski Member of the Institute of Combinatorics and its Applications, Winnipeg, Manitoba, Canada PL-15-674 Bia lystok, Konwaliowa 11/11, Poland e-mail: [email protected] Summary This note is a continuation of [48, 2010]. Firstly, we propose H(x)-binomials' recurrence formula appointed by Ward-Horadam H(x) = hHn(x)in≥0 functions' sequence i.e. any functions' sequence solution of the second order recurrence with functions' coefficients. As a method this comprises H ≡ H(x = 1) num- ber sequences V -binomials' recurrence formula determined by the primordial Lucas sequence of the second kind V = hVnin≥0 as well as its well elaborated companion fundamental Lucas sequence of the first kind U = hUnin≥0 which gives rise in its turn to the known U-binomials' recurrence as in [1, 1878] , [6, 1949], [8, 1964], [12, 1969], [17, 1989] or in [18, 1989] etc. Then we deliver a new type H(x)-binomials' "mixed" recurrence, straightforward n n formula for special case of Ward-Horadam sequences H(x) = hp (x) + q (x)in≥0. Here general H(x)-binomials' array is appointed by Ward-Horadam sequence of functions which in predominantly considered cases where chosen to be polyno- mials. For the sake of combinatorial interpretations and in number theory H(x = 1) = hHn(x = 1)in≥0 is usually considered to be natural or integer numbers valued sequence. Number sequences H = H(x = 1) = hHnin≥0 were also recently called by several authors: Horadam sequences. -
Combinatorially Thinking SIMUW 2008: July 14–25
Combinatorially Thinking SIMUW 2008: July 14–25 Jennifer J. Quinn [email protected] Philosophy. We want to construct our mathematical understanding. To this end, our goal is to situate our problems in concrete counting contexts. Most mathematicians appreciate clever combinatorial proofs. But faced with an iden- tity, how can you create one? This course will provide you with some useful combinatorial interpretations, lots of examples, and the challenge of finding your own combinatorial proofs. Throughout the next two weeks, your mantra should be to keep it simple. Contents 1 Basic Tools 3 1.1 SomeCombinatorialInterpretations . ........... 3 1.2 Counting Technique 1: Ask a Question and Answer Two Ways . ........... 6 1.3 Counting Technique 2: Description-Involution-Exception(DIE) ............ 7 2 Binomial Identities 8 2.1 WorkingTogether ................................. .... 8 2.2 OnYourOwn....................................... 9 n 2.3 What’s the Parity of k ? ................................. 10 3 Fibonacci Identities 13 3.1 TilingwithSquaresandDominoes . ........ 13 3.2 WorkingTogether ................................. .... 14 3.3 OnYourOwn....................................... 15 3.4 CombinatorialProofofBinet’sFormula . ........... 16 4 Generalizations—Lucas, Gibonacci, and Linear Recurrences 18 4.1 MotivatingGeneralization . ......... 18 4.2 WeightingtheTilings ... ... .. ... ... ... ... ... .. ... ...... 19 4.3 WorkingTogether ................................. .... 20 4.4 OnYourOwn...................................... -
The Tilings of a (2 × N)-Board and Some New Combinatorial Identities
1 2 Journal of Integer Sequences, Vol. 20 (2017), 3 Article 17.5.4 47 6 23 11 The Tilings of a (2 × n)-Board and Some New Combinatorial Identities Reza Kahkeshani Department of Pure Mathematics Faculty of Mathematical Sciences University of Kashan Kashan Iran [email protected] Abstract We know that the Fibonacci numbers count the tilings of a (1×n)-board by squares and dominoes, or equivalently, the number of tilings of a (2×n)-board by dominoes. We use the tilings of a (2 × n)-board by colored unit squares and dominoes to obtain some new combinatorial identities. They are generalization of some known combinatorial identities and in the special case give us the Fibonacci identities. 1 Introduction The Fibonacci numbers (A000045), (Fn)n≥0, are the sequence defined by F0 = 0, F1 = 1, and Fn = Fn−1 + Fn−2 for n ≥ 2 [3, 4]. It is easy to see that the tilings of a (1 × n)-board with (1 × 1) squares and (1 × 2) dominoes can be counted by the Fibonacci numbers. In fact, if fn counts such tilings then fn = Fn+1. From now on, we use the word “square(s)” to mean “(1 × 1) square(s)”. The Pell numbers (A000129) are defined by P0 = 0, P1 = 1, and for n ≥ 2, Pn = 2Pn−1 + Pn−2. The Pell number Pn+1 counts the tilings of a (1 × n)-board with dominoes and two colors of squares. Benjamin, Quinn, Plott, and Sellers [1, 2] proved a number of combinatorial identities using these interpretations. McQuistan and Lichtman [6] also studied the tilings of a (2 × n)-board by squares and dominoes for placing dimers on a lattice and proved that kn =3kn−1 + kn−2 − kn−3 1 for n ≥ 3, where kn is the number of such tilings (see Cipra’s comment on (A030186) in OEIS [7]). -
Arxiv:1510.03159V3 [Math.CO] 6 Aug 2016
ANALOGUES OF A FIBONACCI-LUCAS IDENTITY GAURAV BHATNAGAR Abstract. Sury’s 2014 proof of an identity for Fibonacci and Lucas numbers (Identity 236 of Benjamin and Quinn’s 2003 book: Proofs that count: The art of combinatorial proof) has excited a lot of comment. We give an alternate, telescoping, proof of this—and associated— identities and generalize them. We also give analogous identities for other sequences that satisfy a three-term recurrence relation. 1. Lucas’ 1876 identity and its associates Let Fk and Lk be the kth Fibonacci and kth Lucas numbers, respectively, for k = 0, 1, 2,... Both sequences of numbers satisfy a common recurrence relation, for n = 0, 1, 2,... xn+2 = xn+1 + xn; with differing initial values: F0 = 0, F1 = 1 but L0 = 2,L1 = 1. Fibonacci numbers satisfy many identities. The classic 1876 identity is due to Lucas himself: F0 + F1 + F2 + · · · + Fn−1 = Fn+1 − 1, which (in view of the relation Fk+1 + Fk−1 = Lk, for k ≥ 1) can be written as n (Lk − Fk+1)= Fn+1, (1.1) k X=0 where we used 1 = L0 − F1, F0 = L1 − F2, F1 = L2 − F3, and so on. Next consider Identity 236 of Benjamin and Quinn [4, p. 131]: n k n+1 2 Lk = 2 Fn+1. (1.2) k X=0 A recent proof of this identity by Sury [15] excited a lot of comment. Kwong [10] gave an arXiv:1510.03159v3 [math.CO] 6 Aug 2016 alternate proof, and Marques [11] (see also Martinjak [12]) found an analogous identity that replaces 2 by 3. -
PROOFS YOU CAN COUNT on by Helen K. Jenne a Thesis Submitted
PROOFS YOU CAN COUNT ON by Helen K. Jenne A thesis submitted in partial fulfillment of the requirements for graduation with Honors in Mathematics. Whitman College 2013 Certificate of Approval This is to certify that the accompanying thesis by Helen K. Jenne has been accepted in partial fulfillment of the requirements for graduation with Honors in Mathematics. Barry Balof, Ph.D. Whitman College May 8, 2013 ABSTRACT PROOFS YOU CAN COUNT ON Benjamin and Quinn's (2003) proofs by direct counting reduce the proof of a mathematical result to a counting problem. In comparison to other proof techniques such as proof by induction, proofs by direct counting are concrete, satisfying, and accessible to an audience with a variety of mathematical backgrounds. This paper presents proofs by direct counting of identities involving the Fibonacci numbers, the Lucas numbers, continued fractions, and harmonic numbers. We use the Fibonacci numbers and Lucas numbers primarily to introduce proofs by direct counting. We then present Benjamin and Quinn's combinatorial interpretation of continued frac- tions, which allows us to reduce identities involving continued fractions to counting problems. We apply the combinatorial interpretation to infinite continued fractions, and ultimately present a combinatorial interpretation of the continued fraction expan- sion of e. We conclude this paper by discussing Benjamin and Quinn's combinatorial interpretations of harmonic numbers and a generalization of the harmonic numbers called the hyperharmonic numbers. Helen Jenne Whitman College May 2013 i Contents 1 Introduction 1 2 Fibonacci Numbers 3 2.1 Introduction and Background . 3 2.2 Tiling Interpretation . 4 2.3 Proofs by Direct Counting of Fibonacci Identities . -
View This Volume's Front and Back Matter
AMS / MAA DOLCIANI MATHEMATICAL EXPOSITIONS VOL 27 CountProofs the Really The Art of Combinatorial Proof Arthur T. Benjamin Jennifer J. Quinn i i \master" – 2012/1/30 – 15:35 – page i – #1 i i 10.1090/dol/027 Proofs That Really Count The Art of Combinatorial Proof i i i i i i \master" – 2012/1/30 – 15:35 – page ii – #2 i i c 2003 by The Mathematical Association of America (Incorporated) Library of Congress Catalog Card Number 2003108524 Print edition ISBN: 978-0-88385-333-7 Electronic edition ISBN: 978-1-61444-208-0 Printed in the United States of America Current Printing (last digit): 10 9 8 7 6 5 4 i i i i i i \master" – 2013/4/23 – 18:00 – page iii – #3 i i The Dolciani Mathematical Expositions NUMBER TWENTY-SEVEN Proofs That Really Count The Art of Combinatorial Proof Arthur T. Benjamin Harvey Mudd College and Jennifer J. Quinn University of Washington Tacoma Published and Distributed by The Mathematical Association of America i i i i i i \master" – 2012/1/30 – 15:35 – page iv – #4 i i DOLCIANI MATHEMATICAL EXPOSITIONS Committee on Publications GERALD ALEXANDERSON, Chair Dolciani Mathematical Expositions Editorial Board DANIEL J. VELLEMAN, Editor EDWARD J. BARBEAU DONNA L. BEERS ROBERT BURCKEL ROBERT DEVANEY JERROLD GROSSMAN LESTER H. LANGE SANFORD SEGAL WILLIAM S. ZWICKER i i i i i i \master" – 2012/1/30 – 15:35 – page v – #5 i i The DOLCIANI MATHEMATICAL EXPOSITIONS series of the Mathematical Association of America was established through a generous gift to the Association from Mary P.