Ayazoglu, Rabil; Simsek, Ramazan

This paper considers the global boundedness of solutions to the parabolic-elliptic chemotaxis system with a logistic source involving exponents that depend on spatial variables and nonlinear signal production: (Formula presented.) where (Formula presented.), μ, (Formula presented.), and (Formula presented.) is a measurable function, subject to the homogeneous Neumann boundary conditions in a bounded domain (Formula presented.) with smooth boundary. We prove that if either (Formula presented.), (Formula presented.) or (Formula presented.) with (Formula presented.) or (Formula presented.) with (Formula presented.), (Formula presented.) or (Formula presented.), then the above system possesses a unique global bounded classical solution.

AtıfScopus1·WoS1·OpenAlex1

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Ayazoglu, Rabil; Simsek, Ramazan

This paper deals with the following parabolic-parabolic chemotaxis system with growth source { u _ t = ∇· (γ (ε) ∇ u) - ∇· (χ (ε) u ∇v) + η (x) u - μ (x) u ^ α, x ∈Ω, t > 0,; v _ t = Δ v - v + u ^ β, x ∈Ω, t > 0, ]. under homogeneous Neumann boundary conditions in a smooth bounded domain Ω⊂ℝ^N (N≥ 2), and the parameters β >0, α >1, and γ ,χ are positive motility functions. Moreover, we assume that η (x) ^ m + α - 1/α - 1/(μ (x) - μ_ *) ^ m/α - 1 is integrable for some m ≥ 1, where η(·) and μ(·) are positive measurable functions satisfying μ(x) > μ_* > 0 for almost every x ∈Ω. Under these conditions, if α > max{2β, 2}, then the system possesses a unique global bounded classical solution.

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Ayazoglu, Rabil; Akkoyunlu, Ebubekir; Naghizadeh, Zohreh

We consider an initial boundary value problem for a class of anisotropic parabolic Ni-Serrin type equations with nonstandard nonlinearity in a bounded smooth domain with homogeneous Dirichlet boundary condition. Because the nonlinear perturbation leads to difficulties (it does not have a definite sign) in obtaining a priori estimates in the energy method, we had to modify the Tartar method significantly. Under suitable assumptions, we obtain the global existence, decay and extinction of solutions.

AtıfWoS1·OpenAlex1

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Ayazoglu, Rabil; Ekincioglu, Ismail

This paper deals with the following competitive two-species chemotaxis system with two chemicals with a source term of logistic type ut=Δu−χ1∇⋅(u∇υ)+η1u−μ1u2, υt=Δυ−υ+ω, ωt=Δω−χ2∇⋅(ω∇z)+η2ω−μ2ω2, 0=Δz−z+u, (x,t)∈Ω×(0,T) under homogeneous Neumann boundary conditions [Formula presented] and initial conditions u(x,0)=u0(x), υ(x,0)=υ0(x), ω(x,0)=ω0(x), x∈Ω, in a bounded domain Ω⊂RN (N≥1), where the parameters χ1, μ1, μ2>0 and η1, η2, χ2∈R. It is proved that the corresponding initial-boundary value problem possesses a unique global bounded classical solution if one of the following cases holds: (i)χ2≤0, (ii)χ2>0 as well as μ2 is large enough, which partially improves the results of [25].

AtıfScopus2·WoS2·OpenAlex2

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Ayazoglu, Rabil

We study the quasilinear attraction–repulsion chemotaxis system of parabolic–elliptic type with logistic source involving the exponents depending on the spatial variables: ut=Δu-χ∇·uu+1r-1∇υ+ξ∇·uu+1r-1∇ω+au-bum(x), 0=Δυ-βυ+αu, 0=Δω-δω+γu, where α, β, δ, γ, χ, ξ, b>0, a≥0, r∈R and m:Ω→1,∞ is a measurable function, subject to the homogeneous Neumann boundary conditions in a bounded domain RNN≥1 with smooth boundary. We prove that this system possesses a unique global bounded classical solution, which is an extension of known results, if the repulsion cancels the attraction in the sense that (balance) χα=ξγ with essinfx∈Ωmx>r+N-2+N,1, and if the attraction prevails over the repulsion in the sense that χα>ξγ with essinfx∈Ωmx>maxr+1,1, and if the repulsion prevails over the attraction in the sense that χα<ξγ.

AtıfScopus2·WoS2

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Ayazoglu, Rabil; Salmanova, Kamala A.

This paper deals with the higher dimension quasilinear parabolic-parabolic chemotaxis model involving a source term of logistic type (formula presented), subject to the homogeneous Neumann boundary conditions in a Ω ⊂ RN (N ≥ 1) with smooth boundary. It is shown that for the attractionrepulsion case with χ2 ≤ 0, the global boundedness of solutions can be ensured by µ1, µ2 > 0 without any other assumptions, due to the contribution of the logistic sources included in addition to the repulsion mechanism. While for the attraction-attraction case with χ2 > 0, the global boundedness of solutions has to require logistic coefficients µ1, µ2 > 0 such that µ2 properly large.

AtıfScopus4·OpenAlex4

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Ayazoglu, Rabil; Alisoy, Gulizar; Akbulut, Sezgin; Aydin, Tuba Agirman

In this paper, we consider an initial boundary value problem for a class of p(·)-Laplacian parabolic equation with nonstandard nonlinearity in a bounded domain. By using new approach, we obtain the global and decay of existence of the solutions. Moreover, the precise decay estimates of solutions before the occurrence of the extinction are derived.

AtıfScopus1·WoS1·OpenAlex1

İncele

Ayazoglu, Rabil

We study the quasilinear attraction-repulsion chemotaxis system of parabolic-elliptic type ut = ∆u−χ∇·(u∇υ)+ξ∇·(u∇ω) with nonlinear production 0 = ∆υ −βυ +αus, 0 = ∆ω −δω +γur, subject to the homogeneous Neumann boundary conditions in a bounded domain Ω ⊂ ℝN (N ≥ 3) with smooth boundary. It is proved that for every α, β, δ, γ, χ, ξ > 0 and s ≥ N2,r > N−2/N s, there exists ξ∗ > 0 such that if ξ > ξ∗ and any sufficiently regular initial datum u0(x) ≥ 0, then the model has a unique global classical solution (u, υ, ω), which is bounded in Ω × (0, ∞).

İncele

Ayazoglu, Rabil; Kadakal, Mahir; Akkoyunlu, Ebubekir

We consider the parabolic-elliptic chemotaxis system with the exponents depending on the spatial variables logistic source and nonlinear signal production: ut = ∆u−χ∇·(u∇υ)+f(x, u), (x, t) ∈ Ω×(0, T), 0 = ∆υ−υ+uγ in a bounded domain Ω ⊂ RN (N ≥ 1) with smooth boundary, subject to nonnegative initial data and homogeneous Neumann boundary conditions, where χ > 0, γ ≥ 1 and ∂ν∂ denotes the outward normal derivative on ∂Ω. The logistic function f fulfilling f(x, s) ≤ ηs− µsα(x)+1, η ≥ 0, µ > 0 for all s > 0 with f(x, 0) ≥ 0 ∀x ∈ Ω, where α : Ω → [1, ∞) is a measurable function. It is proved that if 1 ≤ α(x) < ∞ for all x ∈ Ω such that essinfx∈Ω α(x) > γ or essinfx∈Ω α(x) = γ with µ > χ, then there exists a nonnegative classical solution (u, υ) that is global-in-time and bounded. In addition, under the particular conditions γ = 1 and f(x, s) = µ(s − sα(x)+1), if µ is sufficiently large, the global bounded solution (u, υ) satisfies ∥u(·, t) − 1∥L∞(Ω) + ∥υ (·, t) − 1∥L∞(Ω) ≤ Ce− Nk+2 t for all t > 0 with k = min n χ42 12o , C > 0. The global-in-time existence and uniform-in-time boundedness of solutions are established under specific parameter conditions, which improves the known results.

AtıfScopus11·WoS9·OpenAlex11

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Ayazoglu, Rabil; Akkoyunlu, Ebubekir

This paper is concerned with the blow-up time of the solutions to an integro-differential problem of parabolic type with variable growth if blow-up occurs. By using the differential inequality technique, we obtain lower bounds for the blow-up time and some global existence results under some conditions to variable exponent of reaction, memory kernel, and initial value.

AtıfScopus1·WoS1

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Aydin, Tuba Agirman; Ayazoglu, Rabil; Kocayigit, Huseyin

In this paper, we define timelike curves in R-2(4) and characterize such curves in terms of Frenet frame. Also, we examine the timelike helices of R-2(4), taking into account their curvatures. In addition, we study timelike slant helices, timelike B-1-slant helices, timelike B-2-slant helices in four dimensional semi-Euclidean space, R-2(4). And then we obtain an approximate solution for the timelike B-1 slant helix with Taylor matrix collocation method.

AtıfWoS1

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Ayazoglu, Rabil; Ekincioglu, Ismail; Şener, S. Şule

We investigate the problem of approximating function f in the power-type weighted variable exponent Sobolev space (Formula presented), by the Hardy averaging operator (Formula presented). If α(.) x 0 the function f lies in the power-type weighted variable exponent Sobolev space (Formula presented) (0, 1), it is shown that (Formula presented), where C is a positive constant. Moreover, we consider the problem of boundedness of Hardy averaging operator A in power-type weighted variable exponent grand Lebesgue spaces (Formula presented) (0, 1). The sufficient α(.) criterion established on the power-type weight function α(.) and exponent p(.) for the Hardy averaging operator to be bounded in these spaces.

AtıfScopus3·WoS4·OpenAlex3

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Ayazoglu, Rabil

This paper deals with the higher dimension quasilinear parabolic-parabolic Keller-Segel system involving a source term of variable logistic type ut=∇⋅(ϕ(u)∇u)−∇⋅(ψ(u)∇υ)+g(x,u), −Δυ=−υ+u, in (x,t)∈Ω×(0,T), subject to nonnegative initial data and homogeneous Neumann boundary condition, where Ω is a smooth and bounded domain in RN (N≥1) and g∈C1(Ω‾×[0,∞)) function satisfies g(x,s)≤ηsk(x)−μsm(x),s>0 with g(x,0)≥0, x∈Ω and η≥0,μ>0 are constants, k,m are measurable functions with 1<k−:=ess infx∈Ωk(x)≤k(x)≤k+:=esssup k(x)x∈Ω<+∞, 2≤m−:=ess infx∈Ωm(x)≤m(x)≤m+:=esssup m(x)x∈Ω<+∞. Positive functions ψ,ϕ∈C2([0,∞)) satisfy νsq≤ψ≤χsq and ϕ≥σsp with p,q∈R, ν,χ,σ>0 when s≥0. It is proved that if q=m−−1 (critical case) and [Formula presented] then there exists a classical solution which is global in time and bounded. Moreover, if q∈(k+−1,m−−1), we obtain that there is a classical solution of the above system uniformly in time bounded without any restrictions on m− and μ.

AtıfScopus10·WoS8·OpenAlex10

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Ayazoglu, Rabil; Akkoyunlu, Ebubekir

This paper deals with the higher dimension quasilinear parabolic–parabolic chemotaxis model involving a source term of logistic type ut= ∇ · (ϕ(u) ∇ u) - ∇ · (ψ(u) ∇ υ) + g(x, u) , τυt= Δ υ- υ+ u, in(x,t)∈Ω×(0,T), subject to nonnegative initial data and homogeneous Neumann boundary condition, where Ω is a smooth and bounded domain in RN, N≥ 1 and ψ, ϕ, g are smooth, positive functions satisfying νsq≤ ψ≤ χsq, ϕ≥ σsp, p, q∈ R, ν, χ, σ> 0 when s≥ s> 1 , g(x, s) ≤ ηsk(x)- μsm(x) for s> 0 , η≥ 0 , μ> 0 constants and g(x, 0) ≥ 0 , x∈ Ω , where k, m are measurable functions with 0≤k-:=essinfx∈Ωk(x)≤k(x)≤m+:=esssupk(x)x∈Ω<+∞, 1<m-:=essinfx∈Ωm(x)≤m(x)≤m+:=esssupm(x)x∈Ω<+∞. We extend the constant exponents k= { 0 , 1 } , m> 1 which in logistic source term g(s) ≤ ηsk- μsm for s> 0 , η≥ 0 , μ> 0 as variable exponents k(·) ≥ 0 , m(·) > 1 with k+< m-. It is proved that if q= m-- 1 (critical case) with μ properly large that μ > μ for some μ> 0 , then there exists a classical solution which is global in time and bounded. Furthermore, if q< m-- 1 , we prove that the classical solutions to the above system are uniformly in-time-bounded without restriction on μ.

AtıfScopus10·WoS8·OpenAlex10

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Ayazoglu, Rabil; Akkoyunlu, Ebubekir; Aydin, Tuba Agirman

This paper is concerned with the blow-up of the solutions to a semilinear heat equation with a reaction given by parametric variable sources. Some conditions to parameters and exponents of sources are given to obtain lower–upper bounds for the time of blow-up and some global existence results.

AtıfScopus3·WoS2·OpenAlex2

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Ayazoglu, Rabil; Saraç, Yeşim; Şener, S. Şule; Alisoy, Gülizar

In this paper, by using variational approach, Mountain Pass Theorem and Krasnoselskii’s genus theory, we show the existence and multiplicity of solutions for a Schrödinger–Kirchhoff type equation involving the fractional p(. ,.) -Laplacian in fractional Sobolev space with variable exponent. We also establish a Bartsch–Wang type compact embedding theorem for fractional Sobolev space with variable exponent.

AtıfScopus21·WoS22·OpenAlex22

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Hasanov, Javanshir J.; Ayazoglu, Rabil; Bayrakci, Simten

In this article, we consider the Laplace-Bessel differential operator Δ B k, n = a' i = 1 k a, 2 a, x i 2 + γ i x i a, a, x i + a' i = k + 1 n a, 2 a, x i 2, γ 1 > 0,γ k > 0. {\Delta }{{B}{k,n}}=\mathop{\sum }\limits{i=1}{k}\left(\frac{{\partial }{2}}{\partial {x}{i}{2}}+\frac{{\gamma }{i}}{{x}{i}}\frac{\partial }{\partial {x}{i}}\right)+\mathop{\sum }\limits{i=k+1}{n}\frac{{\partial }{2}}{\partial {x}{i}{2}},{\gamma }{1}\gt 0,\ldots,{\gamma }{k}\gt 0. Furthermore, we define B-maximal commutators, commutators of B-singular integral operators and B-Riesz potentials associated with the Laplace-Bessel differential operator. Moreover, we also obtain the boundedness of the B-maximal commutator M b, γ {M}{b,\gamma } and the commutator [ b, A γ[ {[}b,{A}{\gamma }] of the B-singular integral operator and Hardy-Littlewood-Sobolev-type theorem for the commutator [ b, I α, γ[ {[}b,{I}{\alpha,\gamma }] of the B-Riesz potential on B-Morrey spaces L p, λ, γ {L}{p,\lambda,\gamma }, when b â BMO γ b\in {\text{BMO}}{\gamma }.

AtıfScopus5·WoS5·OpenAlex7

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Ayazoglu, Rabil; Şule Şener, Sidika; Aydın, Tuba Ağırman

The present paper is concerned with the resonant problem −div (a (x, ∇u)) = λ1|u|p −2 u + f (x, u) − g(x) in Ω, where Ω is a bounded domain with smooth boundary in RN (N ≥ 2), p ∈ (1, ∞) and div(a (x, ∇u)) is a general elliptic operators in divergence form. By assuming a Landesman-Lazer type condition and using a variational method based on the Minimum Principle, we show the existence of a weak solution in the Sobolev space W0 1,p (Ω).

İncele

Ayazoglu, Rabil; Akbulut, Sezgin; Akkoyunlu, Ebubekir

In this paper, we prove the existence of multiple solutions for the nonhomogeneous Schrödinger-Kirchhoff-type problem involving the p(.)-Laplacian (Formula presented.) where b≥0 is a constant, N ≥2, Δp(.)u:=div(|∇u|p(.)−2∇u) is the p(.)-Laplacian operator, (Formula presented.) is Lipschitz continuous, (Formula presented.) is a coercive type potential, (Formula presented.) and (Formula presented.) functions verifying suitable conditions. We propose different assumptions on the nonlinear term (Formula presented.) to yield bounded Palais-Smale sequences and then prove that the special sequences we found converge to critical points, respectively. The solutions are obtained by the Mountain Pass Theorem, Ekeland variational principle, and Krasnoselskii genus theory.

AtıfScopus1·WoS1

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Ayazoglu, Rabil; Akbulut, Sezgin; Akkoyunlu, Ebubekir

In this paper, the Kantorovich operators Kn, n ϵ N are shown to be uniformly bounded in variable exponent Lebesgue spaces on the closed interval [0, 1]. Also an upper estimate is obtained for the difference Kn (f) − f for functions f of regularity of order 1 and 2 measured in variable exponent Lebesgue spaces, which is of interest on its own and can be applied to other problems related to the Kantorovich operators.

AtıfScopus3·WoS3·OpenAlex3

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