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\input zb-ioport
\iteman{io-port 06078580}
\itemau{Wang, Maolin; Hua, Hongbo}
\itemti{More on Zagreb coindices of composite graphs.}
\itemso{Int. Math. Forum 7, No. 13-16, 669-673 (2012).}
\itemab
Summary: For a nontrivial graph $G$, its first and second Zagreb coindices are defined [{\it A. R. Ashrafi}, {\it T. Do\v sli\'c} and {\it A. Hamzeha}, Discrete Appl. Math. 158, No. 15, 1571--1578 (2010; Zbl 1201.05100)], respectively, as $$\align \overline {M}_{1}(G) &= \sum_{uv\notin E(G)}(d_{G}(u)+d_{G}(v)) \text{ and}\\ \overline {M}_{2}(G) &= \sum_{uv\notin E(G)}(d_{G}(u)+d_{G}(v)),\endalign$$ where $d_{G}(x)$ is the degree of vertex $x$ in $G$. In this paper, we obtained some new properties of Zagreb coindices. We mainly give explicit formulae for the first Zagreb coindex of line graphs and total graphs.
\itemrv{~}
\itemcc{}
\itemut{degree; Zagreb indices; Zagreb coindices; line graphs; total graphs}
\itemli{http://www.m-hikari.com/imf/imf-2012/13-16-2012/index.html}
\end