The second Zagreb coindex is a well-known graph invariant defined as the total degree product of all non-adjacent vertex pairs in a graph. The second Zagreb eccentricity coindex is defined analogously to the second Zagreb coindex by replacing the vertex degrees with the vertex eccentricities. In this paper, we present exact expressions or sharp lower bounds for the second Zagreb eccentricity co...

Let G be a connected graph with vertex set V (G) and edge set E(G). The eccentric connectivity index of G, denoted by ξc(G), is defined as ∑ v∈V (G) deg(v)ec(v), where deg(v) is the degree of a vertex v and ec(v) is its eccentricity. In this paper, we propose the edge version of the above index, the edge eccentric connectivity index of G, denoted by ξc e(G), which is defined as ξc e(G) = ∑ f∈E(...

1Sveučilište Josipa Jurja Strossmayera u Osijeku, Medicinski fakultet Osijek, Osijek, Hrvatska 2Klinička bolnica Sveti Duh, Zagreb, Hrvatska 3Hrvatski zavod za hitnu medicinu, Zagreb, Hrvatska 4Medicinski fakultet Sveučilišta u Zagrebu, Zagreb, Hrvatska 5Klinička bolnica Merkur, Zagreb, Hrvatska 1Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia 2University Hosp...

PROTON MAGNETIC RESONANCE SPECTROSCOPY IN HUNTINGTON'S DISEASE ACCOMPANYING NEUROBORRELIOSIS Helena Sarac, David Ozretic, Neven Henigsberg, Pero Hrabac, Ivan Bagaric & Lucija Bagaric-Krakan Department of Neurology, University Hospital Zagreb, Zagreb, Croatia Croatian Institute for Brain Research, Zagreb, Croatia School of Medicine, University of Zagreb, Zagreb, Croatia Department of Radiology, ...

Abstract. For a (molecular) graph G with vertex set V (G) and edge set E(G), the first and second Zagreb indices of G are defined as M1(G) = ∑ v∈V (G) dG(v) 2 and M2(G) = ∑ uv∈E(G) dG(u)dG(v), respectively, where dG(v) is the degree of vertex v in G. The alternative expression of M1(G) is ∑ uv∈E(G)(dG(u) + dG(v)). Recently Ashrafi, Došlić and Hamzeh introduced two related graphical invariants M...

Let G be a graph with vertex set V (G) and edge set E(G) . The first and second multiplicative Zagreb indices of G are Π1 = ∏ x∈V (G) deg(x) 2 and Π2 = ∏ xy∈E(G) deg(x) deg(y) , respectively, where deg(v) is the degree of the vertex v . Let Tn be the set of trees with n vertices. We determine the elements of Tn , extremal w.r.t. Π1 and Π2 . AMS Mathematics Subject Classification (2000): 05C05, ...

Lea Milutinović1, Marijana Braš2,3, Veljko Đorđević3 1University of Zagreb School of Medicine, Student Society for Neuroscience, Zagreb, Croatia, 2Zagreb University Hospital Centre, Department of Psychological Medicine, Zagreb, Croatia, 3University of Zagreb School of Medicine, Centre for Palliative Medicine, Medical Ethics and Communication Skills, Zagreb, Croatia / 1Sveučilište u Zagrebu, Med...

School of Medicine, University of Zagreb, Croatia (VI, MJ); School of Medicine, University of Zagreb, Department of Nephrology, Hypertension, Dialysis and Transplantation, University Hospital Center Zagreb, Croatia (ML, AV, SK, JK, TZ, VP, MZ, BJ); School of Medicine, University of Zagreb, Department of Metabolic Disorders, University Hospital Center Zagreb, Zagreb, Croatia (IP); and School of ...

By the Von Neumann regular graph of R, we mean the graph that its vertices are all elements of R such that there is an edge between vertices x,y if and only if x+y is a von Neumann regular element of R, denoted by G_Vnr (R). For a commutative ring R with unity, x in R is called Von Neumann regular if there exists x in R such that a=a2 x. We denote the set of Von Neumann regular elements by V nr...

1Čakovec General Hospital, Čakovec, Croatia; 2University Hospital Centre Zagreb, Department of Nephrology, Arterial Hypertension, Dialysis and Transplantation, Zagreb, Croatia; 3Sestre milosrdnice University Hospital Centre, Department of Nuclear Medicine, Zagreb, Croatia; 4University Hospital Centre Zagreb, Department of Dermatology and Venereology, Zagreb, Croatia; 5University of Zagreb Schoo...