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The inverse problem for integer-valued topological indices is about the existence of a graph having its index value equal to a given integer. We solve this problem for the first and second Zagreb indices, and present analogous results also for the forgotten and hyper-Zagreb index. The first Zagreb index of connected graphs can take any even positive integer value, except 4 and 8. The same is true if one restricts to trees or to molecular graphs. The second Zagreb index of connected graphs can take any positive integer value, except 2, 3, 5, 6, 7, 10, 11, 13, 15 and 17. The same is true if one restricts to trees or to molecular graphs.

In this paper, we consider an extended KdV equation, which arises in the analysis of several problems in soliton theory. First, we converted the underlying equation into the Hirota bilinear form. Then, using the novel test function method, abundant multi-soliton solutions were obtained. Second, we have performed some distinct methods to extended KdV equation for getting some exact wave solutions. In this regard, Kudryashov’s simplest equation methods were examined. Third, the local conservation laws are deduced by multiplier/homotopy methods. Finally, the graphical simulations of the exact solutions are depicted.

In this study, we consider three model equations of shallow water waves. Shallow water equations model the propagation of strongly nonlinear waves up to breaking and run-up in nearshore zones. We perform multiple exp-function method which is known as a generalization of Hirota's perturbation scheme. We yield one-, two-, and three-wave solutions. The obtained solutions can be used as benchmarks for numerical solutions of the underlying equations. Faculty Research Committee of FAST, North-West University, Mafikeng Campus, SouthAfrica

Let t≥1 be an integer. In this work, we consider the number of integer solutions of Diophantine equation $$x^{2}-(t^{2}+t)y^{2}-(4t+2)x+(4t^{2}+4t)y=0$$ over ℤ and also over finite fields $\mathbb{F}_{p}$ for primes p≥5.

For water levels, generally a non-stationary variable, the technique of universal kriging is applied in preference to ordinary kriging as the interpolation method. Each set of data in every sector can fit different empirical semivariogram models since they have different spatial structures. These models can be classified as circular, spherical, tetraspherical, pentaspherical, exponential, gaussian, rational quadratic, hole effect, K-bessel, J-bessel and stable. This study aims to determine which of these empirical semivariogram models will be best matched with the experimental models obtained from groundwater-table values collected from. Mustafakemalpasa left bank irrigation scheme in 2002. The model having the least error was selected by comparing the observed water-table values with the values predicted by empirical semivariogram models. It was determined that the rational quadratic empirical semivariogram model is the best fitted model for the studied irrigation area.

The aim of this paper is to unify the family of L-functions. By using the generating functions of the Bernoulli, Euler and Genocchi polynomials, we construct unification of the L-functions. We also derive new identities related to these functions. We also investigate fundamental properties of these functions. AMS Subject Classification: 11B68, 11S40, 11S80, 26C05, 30B40. Akdeniz Üniversitesi