In this paper we prove that the set of positive odd integers k such that k&2 n has at least three distinct prime factors for all positive integers n contains an infinite arithmetic progression. The same result corresponding to k2 n +1 is also true.
The crossing number of K1,3,n and K2,3,n
β Scribed by Kouhei Asano
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 234 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
In this article, we will determine the crossing number of the complete tripartite graphs K,.3.n and K2,3.n. Our proof depends on Kleitman's results for the complete bipartite graphs [D. J. Kleitman, The crossing number of K5,n. J. Combhatorial Theory 9 (1970) 375-3231. a graph G is the minimum number among good immersions.
The crossing numbers of the complete bipartite graphs K,,,n were computed by D. J. Kleitman [l], for the case m 5 6. More precisely, he proved that
cr(Km,J = [ i m ] [ f ( ml ) ] [ i n ] [ i ( nl)]
, if m 5 6 .
π SIMILAR VOLUMES
In this article, w e show that the crossing number of K3," in a surface with Euler genus . This generalizes a result of Guy and Jenkyns, who obtained this result for the torus. 0
## Abstract An upper bound on the Ramsey number __r__(__K__~2,__nβs__~,__K__~2,__n__~) where __s__ β₯ 2 is presented. Considering certain __r__(__K__~2,__nβs__~,__K__~2,__n__~)βcolorings obtained from strongly regular graphs, we additionally prove that this bound matches the exact value of __r__(__K
The barium perfluoroalkanedisulfonates Ba(O 3 S) 2 (CF 2 ) n (n = 1, 3Β±5) and the new potassium fluoroalkanedisulfonates K 2 (O 3 S) 2 CHF, K 2 (O 3 S) 2 CF 2 , and K 2 (O 3 S) 2 (CF 2 ) 5 have been prepared by reaction of (CF 2 ) n (SO 2 F) 2 (n = 1, 3Β±5) or CHF(SO 2 F) 2 with CaO (or Ca(OH) 2 ) an