arXiv subjects

Narahari N

Publications and source records attributed to Narahari N.

4 recordsLinked to original sources

arXiv2026

A comparative study of sum-connectivity and product-connectivity Gourava indices for benzenoid hydrocarbons

This study evaluates the sum-connectivity ($SGO$) and product-connectivity ($PGO$) Gourava indices as molecular descriptors for benzenoid hydrocarbons. Using a dataset of 30 benzenoid structures, we compare least-squares regression models for predicting $\pi$-electronic energies ($E_{\pi}$) and find that $SGO$ yields a markedly better fit than $PGO$ across molecular edge types. The indices are further assessed using three validation designs: (i) correlation analysis, in which $SGO$ exhibits strong yet non-perfect inverse correlations with standard descriptors ($M_1, M_2, SO, DSO,$ and $ABS$; $r\in[-0.9923,-0.8936]$), suggesting complementary structural information; (ii) degeneracy analysis on Octane, Nonane, and order-$10$ tree datasets, where $SGO$ attains low degeneracy rates (22.22\%, 40.00\%, and 42.45\%); and (iii) structure-sensitivity analysis on trees of order $n=10$, showing 74\% higher sensitivity than $DSO$ while maintaining a high structure-abruptness ratio ($SA = 0.474386$). Overall, $SGO$ offers a favorable balance between discriminative power and numerical stability, supporting its applicability in QSPR modeling and related theoretical studies.

physics.chem-ph↗

arXiv2026

A Comparative Study of Exponential Sum-Connectivity and Product-Connectivity Gourava Indices for Benzenoid Hydrocarbons

In this work, the exponential sum-connectivity Gourava index ($e^{SGO(G)}$) and the exponential product-connectivity Gourava index ($e^{PGO(G)}$) are computed and comparatively analyzed for benzenoid hydrocarbons. Our results demonstrate that these descriptors exhibit a strong mutual correlation and provide enhanced sensitivity in modeling the structural characteristics of molecular graphs. Regression analysis reveals that both indices are exceptionally reliable predictors of $\pi$-electronic energies, achieving correlation coefficients exceeding $0.999$. Notably, a comparative assessment indicates that the exponential product-connectivity variant offers a slightly superior fit, as its coefficients align more precisely with optimal least-squares results. These findings confirm that both exponential Gourava-based indices provide a robust framework for characterizing electronic properties, with the product-connectivity version showing particular promise for high-precision QSPR studies in benzenoid systems.

physics.chem-ph↗

arXiv2025

Edge Irregularity Strength: A Complementary Descriptor to Topological Indices in QSPR and QSAR Studies

In chemical graph theory, topological indices are widely used as numerical descriptors for establishing quantitative structure-property relationships (QSPR) and quantitative structure-activity relationships (QSAR). These indices successfully correlate molecular structure with various physicochemical and biological properties. In addition to these methods, the concept of edge irregularity strength, a graph labeling measure, offers another perspective for representing structural characteristics. In this context, the edge irregularity strength concept provides a systematic way of assigning numerical labels to atoms based on specific rules. In this work, we explore the chemical applicability of the edge irregularity strength and demonstrate that it can also serve as a predictive tool for physicochemical properties, similar to topological indices. The findings show that the edge irregularity strength captures molecular features and complements existing approaches to structure-property analysis in chemical graph theory.

physics.chem-ph↗

arXiv2024

On edge irregularity strength of cycle-star graphs

For a simple graph $G$, a vertex labeling $ϕ:V(G) \rightarrow \{1, 2,\ldots,k\}$ is called $k$-labeling. The weight of an edge $uv$ in $G$, written $w_ϕ(uv)$, is the sum of the labels of end vertices $u$ and $v$, i.e., $w_ϕ(uv)=ϕ(u)+ϕ(v)$. A vertex $k$-labeling is defined to be an edge irregular $k$-labeling of the graph $G$ if for every two distinct edges $u$ and $v$, $w_ϕ(u) \neq w_ϕ(v)$. The minimum $k$ for which the graph $G$ has an edge irregular $k$-labeling is called the edge irregularity strength of $G$, written $es(G)$. In this paper, we study the edge irregular $k$-labeling for cycle-star graph $CS_{k,n-k}$ and determine the exact value for cycle-star graph for $3 \leq k \leq 7$ and $n-k \geq 1$. Finally, we make a conjecture for the edge irregularity strength of $CS_{k,n-k}$ for $k \geq 8$ and $n-k \geq 1$.

math.CO↗