in this paper we study finding the $(k,l)$-core problem on a tree which the vertices have positive or negative weights. let $t=(v,e)$ be a tree. the $(k,l)$-core of $t$ is a subtree with at most $k$ leaves and with a diameter of at most $l$ which the sum of the weighted distances from all vertices to this subtree is minimized. we show that, when the sum of the weights of vertices is negative, t...

In this paper we study finding the $(k,l)$-core problem on a tree which the vertices have positive or negative weights. Let $T=(V,E)$ be a tree. The $(k,l)$-core of $T$ is a subtree with at most $k$ leaves and with a diameter of at most $l$ which the sum of the weighted distances from all vertices to this subtree is minimized. We show that, when the sum of the weights of vertices is negative, t...

Abstract. In the mid-1980s B.N. Parsons [29] and the author [10] independently had the idea to generalize linear stationary k-step methods to stationary (k, l)-step methods, which were further generalized to nonstationary and even nonlinear (k, l)-step methods. Later, conjugate-gradient-type methods that are (k, l)-step methods of a similar sort were introduced and investigated in the PhD thesi...

Let G=(V,E) be a simple graph with n vertices and m edges, P(G,k) the chromatic polynomial of G, P(G,L) number L-colorings G for any k-assignment L. In this article, we show that when k≥m−1≥3, P(G,L)−P(G,k) is bounded below by ((k−m+1)kn−3+(k−m+3)c3kn−5)∑uv∈E|L(u)∖L(v)|, where c≥(m−1)(m−3)8, in particular, if K3-free, then c≥(m−22)+2m−3. Consequently, P(G,L)≥P(G,k) whenever k≥m−1.

Bu ara?t?rman?n amac? i? tatmininin tu?kenmi?lik u?zerindeki etkisini belirlemek ve bu etkide öz kendilik de?erlendirmesinin arac?l?k rolu?nu? tespit etmektir. Ara?t?rman?n evrenini merkezi Ankara’da bulunan bir kamu iktisadi te?ebbu?su?nde çal??makta olan 850 personel olu?turmaktad?r. örneklemi te?ebbu?su?nu?n Band?rma’daki biriminde 271 ile kolayda örnekleme yöntemiyle edilmi?tir. kurulu?ta a...