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A MINIMUM DEGREE CONDITION FOR FRACTIONAL ID-[a,b]-FACTOR-CRITICAL GRAPHS

Published online by Cambridge University Press:  07 February 2012

SIZHONG ZHOU*
Affiliation:
School of Mathematics and Physics, Jiangsu University of Science and Technology, Mengxi Road 2, Zhenjiang, Jiangsu 212003, PR China (email: [email protected])
ZHIREN SUN
Affiliation:
School of Computer Science, Nanjing Normal University, Nanjing, Jiangsu 210046, PR China
HONGXIA LIU
Affiliation:
School of Mathematics and Informational Science, Yantai University, Yantai, Shandong 264005, PR China
*
For correspondence; e-mail: [email protected]
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Abstract

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Let G be a graph of order n, and let a and b be two integers with 1≤ab. Let h:E(G)→[0,1] be a function. If a≤∑ exh(e)≤b holds for any xV (G), then we call G[Fh] a fractional [a,b] -factor of G with indicator function h, where Fh ={eE(G):h(e)>0}. A graph G is fractional independent-set-deletable [a,b] -factor-critical (in short, fractional ID-[a,b] -factor-critical) if GI has a fractional [a,b] -factor for every independent set I of G. In this paper, it is proved that if n≥((a+2b)(a+b−2)+1 )/b and δ(G)≥((a+b)n )/(a+2b ) , then G is fractional ID-[a,b] -factor-critical. This result is best possible in some sense, and it is an extension of Chang, Liu and Zhu’s previous result.

Type
Research Article
Copyright
Copyright © Australian Mathematical Publishing Association Inc. 2012

Footnotes

This research was supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province (10KJB110003), Jiangsu University of Science and Technology (2010SL101J) and Shandong Province Higher Educational Science and Technology Program (J10LA14), and was sponsored by the Qing Lan Project of Jiangsu Province.

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