twin minus domination in directed graphs

نویسندگان

maryam atapour

department of mathematics faculty of basic sciences university of bonab bonab, iran, po. box: 5551761167 abdollah khodkar

department of mathematics university of west georgia carrollton, ga 30118, usa

چکیده

let $d=(v,a)$ be a finite simple directed graph. a function$f:vlongrightarrow {-1,0,1}$ is called a twin minus dominatingfunction (tmdf) if $f(n^-[v])ge 1$ and $f(n^+[v])ge 1$ for eachvertex $vin v$. the twin minus domination number of $d$ is$gamma_{-}^*(d)=min{w(f)mid f mbox{ is a tmdf of } d}$. inthis paper, we initiate the study of twin minus domination numbersin digraphs and present some lower bounds for $gamma_{-}^*(d)$ interms of the order, size and maximum and minimum in-degrees andout-degrees.

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عنوان ژورنال:
communication in combinatorics and optimization

جلد ۱، شماره ۲، صفحات ۱۴۹-۱۶۴

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