The sigma coindex is defined as the sum of squares differences between degrees all nonadjacent vertex pairs. In this paper, we propose some mathematical properties coindex. Later, present precise results for coindices various graph operations such tensor product, Cartesian lexicographic disjunction, strong union, join, and corona product.

+ Groenemeyer Institute for Microtherapy, 44799 Bochum, Germany, Department of General Surgery and Traumatology, General Hospital Varazdin, I Mestrovica bb, 42000, Varazdin, Croatia, Croatian Institute of Transfusion Medicine, Petrova ulica, 10000, Zagreb, Croatia, Department of Orthopaedic Surgery, School of Medicine, University of Zagreb, Salata 3b, 10000, Zagreb, Croatia, The Scientific Unit...

Adresa za dopisivanje Boris Klaić, Stomatološka poliklinika Perkovčeva 3, HR-10 000 Zagreb [email protected] Sažetak Svrha rada bila je dobiti trodimenzionalne kvalitativne i kvantitativne podatke o topografiji elektropoliranih uzoraka Co-Cr dentalne legure na nano-ljestvici, točnije podatke o dvjema različitim čvrstim fazama opisanima u literaturi kao dendriti i interdendritski prostori. Materijal...

1 Karmela Aleksic-Maslac, University of Zagreb, Faculty of Electrical Engineering and Computing, Unska 3, Zagreb, Croatia, [email protected] 2 Branko Jeren, University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia, [email protected] 3 Zvonko Kostanjcar (Student), University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia, Zvonko.K...

Let G be a simple connected graph. The first and second Zagreb indices have been introduced as  vV(G) (v)2 M1(G) degG and M2(G)  uvE(G)degG(u)degG(v) , respectively, where degG v(degG u) is the degree of vertex v (u) . In this paper, we define a new distance-based named HyperZagreb as e uv E(G) . (v))2 HM(G)     (degG(u)  degG In this paper, the HyperZagreb index of the Cartesian p...

‎The first multiplicative Zagreb index $Pi_1(G)$ is equal to the‎ ‎product of squares of the degree of the vertices and the second‎ ‎multiplicative Zagreb index $Pi_2(G)$ is equal to the product of‎ ‎the products of the degree of pairs of adjacent vertices of the‎ ‎underlying molecular graphs $G$‎. ‎Also‎, ‎the multiplicative sum Zagreb index $Pi_3(G)$ is equal to the product of‎ ‎the sum...

the first zagreb index $m_1$ of a graph $g$ is equal to the sum of squaresof degrees of the vertices of $g$. goubko proved that for trees with $n_1$pendent vertices, $m_1 geq 9,n_1-16$. we show how this result can beextended to hold for any connected graph with cyclomatic number $gamma geq 0$.in addition, graphs with $n$ vertices, $n_1$ pendent vertices, cyclomaticnumber $gamma$, and minimal $m...

Merkur Clinical Hospital, Zagreb University School of Medicine, Department of Internal medicine, Zagreb, 1Zadar General Hospital, Department of Nephrology and Dialysis, Zadar, 2Bjelovar General Hospital, Department of Internal medicine, Bjelovar, 3Dubrava University Hospital, Department of Nephrology, Zagreb, 4Dubrovnik General Hospital, Department of Internal medicine, Dubrovnik and 5Rijeka Un...

in this paper we study the zagreb index in bucket recursive trees containing buckets with variable capacities. this model was introduced by kazemi in 2012. weobtain the mean and variance of the zagreb index andintroduce a martingale based on this quantity.

The Zagreb indices are the oldest graph invariants used in mathematical chemistry to predict the chemical phenomena. In this paper we define the multiple versions of Zagreb indices based on degrees of vertices in a given graph and then we compute the first and second extremal graphs for them.