We give sharp upper bounds on the Zagreb indices and lower bounds on the Zagreb coindices of chemical trees and characterize the case of equality for each of these topological invariants.

The F-index of a graph is defined as the sum of cubes of the vertex degrees of the graph. In this paper, we introduce a new invariant which is named as F-coindex. Here, we study basic mathematical properties and the behavior of the newly introduced F-coindex under several graph operations such as union, join, Cartesian product, composition, tensor product, strong product, corona product, disjun...

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.

When a finite group freely acts on topological space, we can define its index and coindex. They roughly measure the size of given action. We explore interaction between this theory dynamics. Given fixed-point free dynamical system, set [Formula: see text]-periodic points admits natural action text] for each prime number text]. are interested in growth coindex as Our main result shows that there...

In this study, the explicit expressions for F-index and coindex of derived graphs such as a line graph, subdivision graph, vertex-semitotal graph, edge-semitotal graph, total graph and paraline graph (line graph of the subdivision graph) are obtained.

In this paper, we obtain some upper and lower bounds for the general extended energy of a graph. As an application, we obtain few bounds for the (edge) Zagreb energy of a graph. Also, we deduce a relation between Zagreb energy and edge-Zagreb energy of a graph $G$ with minimum degree $delta ge2$. A lower and upper bound for the spectral radius of the edge-Zagreb matrix is obtained. Finally, we ...

‎let g=(v,e) be a simple connected graph with vertex set v and edge set e. the first, second and third zagreb indices of g are respectivly defined by: $m_1(g)=sum_{uin v} d(u)^2, hspace {.1 cm} m_2(g)=sum_{uvin e} d(u).d(v)$ and $ m_3(g)=sum_{uvin e}| d(u)-d(v)| $ , where d(u) is the degree of vertex u in g and uv is an edge of g connecting the vertices u and v. recently, the first and second m...

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, ...

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...