Dirac proved in 1952 that every 2-connected graph of order n and minimum degree k admits a cycle of length at least minfn; 2kg: As a possible improvement, Woodall conjectured in 1975 that if a 2-connected graph of order n has at least n 2 ΓΎ k vertices of degree at least k; then it has a cycle of len
On a Conjecture of Chalk
β Scribed by Ping Ding
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 261 KB
- Volume
- 65
- Category
- Article
- ISSN
- 0022-314X
No coin nor oath required. For personal study only.
β¦ Synopsis
Let f # Z[x] with degree k and let p be a prime. By a complete trigonometric sum we mean a sum of the form S(q, f )= q x=1 e q ( f (x)), where q is a positive integer and e q (:)=exp(2?if (x)Γq). Professor Chalk made a conjecture on the upper bound of S(q, f ) when q is a prime power. We prove Chalk's conjecture, in the affirmative, if p is relatively small but 3. When p 3 is relatively large, we give an alternative upper bound which is best possible. For p=2, we also improve previous results.
1997 Academic Press
Note that the inequality p t k is a trivial consequence of (3). Let r=r( f ) denote the number of distinct roots of the congruence p &t f $(x)#0(mod p) (0 x<p).
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