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In this paper, we study a new generalization of the Lorentz cone $$\mathcal{L}^n_+$$ L + n , called the monotone extended second-order cone (MESOC). We investigate basic properties of MESOC including computation of its Lyapunov rank and proving its reducibility. Moreover, we show that in an ambient space, a cylinder is an isotonic projection set with respect to MESOC. We also examine a nonlinear complementarity problem on a cylinder, which is equivalent to a suitable mixed complementarity problem, and provide a computational example illustrating applicability of MESOC.

The purpose of this paper is to present an inexact version of the scaled gradient projection method on a convex set, which is inexact in two sense. First, an inexact projection on the feasible set is computed, allowing for an appropriate relative error tolerance. Second, an inexact non-monotone line search scheme is employed to compute a step size which defines the next iteration. It is shown that the proposed method has similar asymptotic convergence properties and iteration-complexity bounds as the usual scaled gradient projection method employing monotone line searches., Comment: 30 pages, 14 figures

Coordinate descent algorithms are popular in machine learning and large-scale data analysis problems due to their low computational cost iterative schemes and their improved performances. In this work, we define a monotone accelerated coordinate gradient descent-type method for problems consisting of minimizing $$f+g$$ , where f is quadratic and g is nonsmooth and non-separable and has a low-complexity proximal mapping. The algorithm is enabled by employing the forward–backward envelope, a composite envelope that possess an exact smooth reformulation of $$f+g$$ . We prove the algorithm achieves a convergence rate of $$O(1/k^{1.5})$$ in terms of the original objective function, improving current coordinate descent-type algorithms. In addition, we describe an adaptive variant of the algorithm that backtracks the spectral information and coordinate Lipschitz constants of the problem. We numerically examine our algorithms on various settings, including two-dimensional total-variation-based image inpainting problems, showing a clear advantage in performance over current coordinate descent-type methods.

In this paper, we investigate the solvability for a coupled system involving nonlinear fractional q-difference stationary Schrodinger equation. The existence criterion of solutions is established by Schauder fixed point theorem, while the existence of iterative positive solutions is derived by monotone iteration method. As applications, an example is presented to illustrate the main results.

Team formation plays an essential role in the labor market. In this paper, we propose two bicriteria algorithms to construct a balance between gain and cost in a team formation problem under the streaming model, subject to a cardinality constraint. We formulate the problem as maximizing the difference of a non-negative normalized monotone submodular function and a non-negative linear function. As an extension, we also consider the case where the first function is $$\gamma $$ -weakly submodular. Combining the greedy technique with the threshold method, we present bicriteria streaming algorithms and give detailed analysis for both of these models. Our analysis is competitive with that in Ene’s work.

This paper is contributed to the structural stability of multi-wave configurations to Cauchy problem for the compressible non-isentropic Euler system with adiabatic exponent γ ∈ (1, 3]. Given some small BV perturbations of the initial state, the author employs a modified wave front tracking method, constructs a new Glimm functional, and proves its monotone decreasing based on the possible local wave interaction estimates, then establishes the global stability of the multi-wave configurations, consisting of a strong 1-shock wave, a strong 2-contact discontinuity, and a strong 3-shock wave, without restrictions on their strengths.

In this paper, we study the problem of maximizing a monotone non-decreasing submodular function $$f :2^\Omega \rightarrow {\mathbb {R}}_{+}$$ subject to a cardinality constraint, i.e., $$\max \{ f(A) : |A| \le k, A \subseteq \Omega \} $$ . We propose a deterministic algorithm based on a new greedy strategy for solving this problem. We prove that when the objective function f satisfies certain assumptions, the algorithm we propose can return a $$1 - \kappa _f (1 - \frac{1}{k})^k$$ approximate solution with O(kn) value oracle queries, where $$\kappa _f$$ is the curvature of the monotone submodular function f. We also show that our algorithm outperforms the traditional greedy algorithm in some cases. Furthermore, we demonstrate how to implement our algorithm in practice.

In this paper we introduce the notions of continuity, meet continuity and quasicontinuity of Δ-spaces, where a Δ-space is a monotone determined, weak monotone convergence space. We prove that: a Δ-space $(X, \mathcal {O}(X))$ is continuous iff the topology lattice $\mathcal {O}(X)$ is completely distributive; a Δ-space $(X, \mathcal {O}(X))$ is meet continuous iff $\mathcal {O}(X)$ is a complete Heyting algebra; a Δ-space $(X, \mathcal {O}(X))$ is continuous iff it is both meet continuous and quasicontinuous. The concepts of continuity, s2-continuity, 𝜃-continuity, strong continuity of posets are shown to be special cases of the continuity of Δ-spaces. We also introduce a type of directed completion of Δ-spaces, called Scott completion. For each Δ-space $(X, \mathcal {O}(X))$ , the topology lattice $\mathcal {O}(X)$ is isomorphic to the topology lattice of its Scott completion. The D-completion, D𝜃-completion and $D_{s_{2}}$ -completion of posets are included in the Scott completion.

This paper investigates dynamically consistent updates of weighted unanimity rules given by variational Bewley preferences (VBP), a class of incomplete preferences characterized by pairs of utility index over consequences and ambiguity index over priors. We show that these dynamically consistent updates are also VBP that preserves the same ranking over consequences and feature conditional ambiguity index obtained through the full Bayesian update of the unconditional one. Moreover, we study conditional forced-choice relations, which capture choices that a decision-maker must take after learning some event. Formally, they are monotone continuous weak orders. We show that any conditional forced-choice relation that preserves the ambiguity attitude of a given unconditional VBP has a variational representation with the same affine utility function over consequences and the ambiguity index of its corresponding dynamically consistent update. Thus, our result provides a novel foundation for full Bayesian updating of variational preferences.

We continue our study of a new boundedness condition for affine permutations, motivated by the fruitful concept of periodic boundary conditions in statistical physics. We focus on bounded affine permutations of size $N$ that avoid the monotone decreasing pattern of fixed size $m$. We prove that the number of such permutations is asymptotically equal to $(m-1)^{2N} N^{(m-2)/2}$ times an explicit constant as $N\to\infty$. For instance, the number of bounded affine permutations of size $N$ that avoid $321$ is asymptotically equal to $4^N (N/4\pi)^{1/2}$. We also prove a permuton-like result for the scaling limit of random permutations from this class, showing that the plot of a typical bounded affine permutation avoiding $m\cdots1$ looks like $m-1$ random lines of slope $1$ whose $y$ intercepts sum to $0$.

In this paper we study the principal spectral theory and asynchronous exponential growth for age-structured models with nonlocal diffusion of Neumann type. First, we provide two general sufficient conditions to guarantee existence of the principal eigenvalue of the age-structured operator with nonlocal diffusion. Then we show that such conditions are also enough to ensure that the semigroup generated by solutions of the age-structured model with nonlocal diffusion exhibits asynchronous exponential growth. Compared with previous studies, we prove that the semigroup is essentially compact instead of eventually compact, where the latter is usually obtained by showing the compactness of solution trajectories. Next, following the technique developed in Vo (Principal spectral theory of time-periodic nonlocal dispersal operators of Neumann type. arXiv:1911.06119 , 2019), we overcome the difficulty that the principal eigenvalue of a nonlocal Neumann operator is not monotone with respect to the domain and obtain some limit properties of the principal eigenvalue with respect to the diffusion rate and diffusion range. Finally, we establish the strong maximum principle for the age-structured operator with nonlocal diffusion.

The paper concerns with a new iterative method for solving a monotone variational inclusion problem in a Hilbert space. The method is of the proximal contraction type incorporated with the regularization technique. Under the prediction stepsize conditions, we establish the strong convergence of the iterative sequences generated by the method to a particular solution of the problem satisfying a variational inequality problem. Finally, we give some numerical examples to illustrate the behavior of the new method in comparison with existing ones.

We construct a continuous nowhere monotone and nondifferentiable function depending on a single parameter q0 ϵ (0; 1). For functions from this continual class, we describe their structural, variational, fractal, and integrodifferential properties.

It is the purpose of this paper to introduce an iterative process which converges strongly to a common point of the set of solutions of a finite family of generalized equilibrium problems, the set of fixed points of a finite family of continuous asymptotically quasi- $$\phi$$ -nonexpansive mappings in the intermediate sense, and the set of zeros of a finite family of $$\gamma$$ -inverse strongly monotone mappings in uniformly convex and uniformly smooth real Banach space. Our results improve and unify most of the results that have been proved for this important class of nonlinear mappings.

In this paper, we propose a numerical approach for solving composite primal-dual monotone inclusions with a priori information. The underlying a priori information set is represented by the intersection of fixed point sets of a finite number of operators, and we propose and algorithm that activates the corresponding set by following a finite-valued random variable at each iteration. Our formulation is flexible and includes, for instance, deterministic and Bernoulli activations over cyclic schemes, and Kaczmarz-type random activations. The almost sure convergence of the algorithm is obtained by means of properties of stochastic Quasi-Fej\'er sequences. We also recover several primal-dual algorithms for monotone inclusions in the context without a priori information and classical algorithms for solving convex feasibility problems and linear systems. In the context of convex optimization with inequality constraints, any selection of the constraints defines the a priori information set, in which case the operators involved are simply projections onto half spaces. By incorporating random projections onto a selection of the constraints to classical primal-dual schemes, we obtain faster algorithms as we illustrate by means of a numerical application to a stochastic arc capacity expansion problem in a transport network., Comment: 23 Pages, 4 figures, 4 Tables

We are interested in the optimal control problem associated with certain quadratic cost functionals depending on the solution $X=X^\alpha$ of the stochastic mean-field type evolution equation in $\mathbb R^d$ $dX_t=b(t,X_t,\mathcal L(X_t),\alpha_t)dt+\sigma(t,X_t,\mathcal L(X_t),\alpha_t)dW_t,$ $X_0\sim \mu$ given, under assumptions that enclose a sytem of FitzHugh-Nagumo neuron networks, and where for practical purposes the control $\alpha_t$ is deterministic. To do so, we assume that we are given a drift coefficient that satisfies a one-sided Lipshitz condition, and that the dynamics is subject to a (convex) level set constraint of the form $\pi(X_t)\leq0$. The mathematical treatment we propose follows the lines of the recent monograph of Carmona and Delarue for similar control problems with Lipshitz coefficients. After addressing the existence of minimizers via a martingale approach, we show a maximum principle and then numerically investigate a gradient algorithm for the approximation of the optimal control., Comment: 32 pages; 11 figures

An edge-ordered graph is a graph with a total ordering of its edges. A path $$P=v_1v_2\ldots v_k$$ in an edge-ordered graph is called increasing if $$(v_iv_{i+1}) < (v_{i+1}v_{i+2})$$ for all $$i = 1,\ldots,k-2$$ ; and it is called decreasing if $$(v_iv_{i+1}) > (v_{i+1}v_{i+2})$$ for all $$i = 1,\ldots,k-2$$ . We say that P is monotone if it is increasing or decreasing. A rooted tree T in an edge-ordered graph is called monotone if either every path from the root to a leaf is increasing or every path from the root to a leaf is decreasing. Let G be a graph. In a straight-line drawing D of G, its vertices are drawn as different points in the plane and its edges are straight line segments. Let $$\overline{\alpha}(G)$$ be the largest integer such that every edge-ordered straight-line drawing of G contains a monotone non-crossing path of length $$\overline{\alpha}(G)$$ . Let $$\overline{\tau}(G)$$ be the largest integer such that every edge-ordered straight-line drawing of G contains a monotone non-crossing complete binary tree of $$\overline{\tau}(G)$$ edges. In this paper we show that $$\overline \alpha(K_n) = \Omega(\log\log n)$$ , $$\overline \alpha(K_n) = O(\log n), \overline \tau(K_n) = \Omega(\log\log \log n)$$ and $$\overline \tau(K_n) = O(\sqrt{n \log n})$$ .

In this paper, we propose an accelerated variant of the proximal point algorithm for computing a zero of an arbitrary maximally monotone operator A. The method incorporates an inertial term (based upon the acceleration techniques introduced by Nesterov), relaxation factors and a correction term. In a general Hilbert space setting, we obtain the weak convergence of the iterates $$(x_n)$$ to equilibria, with the fast rate $$\Vert x_{n+1}-x_{n}\Vert =o(n^{-1})$$ (for the discrete velocity). In particular, when using constant proximal indexes, we establish the accuracy of $$(x_n)$$ to a zero of A with the worst-case rate $$\Vert A_{\lambda }(x_n)\Vert =o(n^{-1})$$ ( $$A_{\lambda }$$ being the Yosida regularization of A with some index $$\lambda $$ ). Furthermore, given any positive integer p and using an appropriate adjustment of increasing proximal indexes, we obtain the worst-case convergence rate $$\Vert A_{\lambda }(x_n)\Vert =o(n^{-(p+1)})$$ . This acceleration process can be applied to various proximal-type algorithms such as the augmented Lagrangian method, the alternating direction method of multipliers, operator splitting methods and so on. Our methodology relies on a Lyapunov analysis combined with a suitable reformulation of the considered algorithm. Numerical experiments are also performed.

Mutually unbiased measurements are a generalization of mutually unbiased bases in which the measurement operators need not to be rank one projectors. In a $d$-dimension space, the purity of measurement elements ranges from $1/d$ for the measurement operators corresponding to maximally mixed states to $1$ for the rank one projectors. In this contribution, we provide a class of MUM that encompasses the full range of purity. Similar to the MUB in which the operators corresponding to different outcomes of the same measurement commute mutually, our class of MUM possesses this sense of compatibility within each measurement. This makes the provided class more similar to the MUB, so that the main difference between them and MUB is due to the purity of the measurement operators. The spectra of these MUMs provides a way to construct a class of $d$-dimensional orthogonal matrices which leave the vector of equal components invariant. Based on this property, and by using the MUM-based entanglement witnesses, we investigate the role of purity to detect entanglement of bipartite states., Comment: 9 pages

Funding for open access charge: Universidad de Granada / CBUA., The authors are grateful to Margarita Arias, Jos´e Antonio G´alvez and Francisco Martín for helpful comments during the preparation of this manuscript., In this paper, we study phi-minimal surfaces in R-3 when the function phi is invariant under a two-parametric group of translations. Particularly those which are complete graphs over domains in R-2. We describe a full classification of complete flat-embedded phi-minimal surfaces if phi is strictly monotone and characterize rotational phi-minimal surfaces by its behavior at infinity when phi has a quadratic growth., Universidad de Granada / CBUA

We introduce a dynamical system to the problem of finding zeros of the sum of two maximally monotone operators. We investigate the existence, uniqueness and extendability of solutions to this dynamical system in a Hilbert space. We prove that the trajectories of the proposed dynamical system converge strongly to a primal–dual solution of the considered problem. Under explicit time discretization of the dynamical system we obtain the best approximation algorithm for solving coupled monotone inclusion problem.

This work examines the existence of the solutions of a class of three-point nonlinear boundary value problems that arise in bridge design due to its nonlinear behavior. A maximum and anti-maximum principles are derived with the support of Green’s function and their constant sign. A different monotone iterative technique is developed with the use of lower solution x(z) and upper solution y(z). We have also discussed the classification of well ordered ( $$x\le y$$ ) and reverse ordered ( $$ y\le x$$ ) cases for both positive and negative values of $$ \sup \left( \frac{\partial f}{\partial w}\right) $$ . Established results are verified with the help of some examples.

We establish conditions to ensure global stability of a competitive periodic system from hypotheses on individual maps. We study planar competitive maps of Kolgomorov type. We show how conditions for global stability for individual maps will remain invariant under composition and hence establish a globally stable cycle. Our main theoretical contribution is to show that stability for monotone non-autonomous periodic maps can be reduced to a problem of global injectivity. We provide analytic conditions that can be checked and illustrate our results with important competition models such as the planar Leslie-Gower and Ricker maps.

Splitting algorithms for finding a zero of sum of operators often involve multiple steps which are referred to as forward or backward steps. Forward steps are the explicit use of the operators and backward steps involve the operators implicitly via their resolvents. In this paper, we study an adaptive splitting algorithm for finding a zero of the sum of three operators. We assume that two of the operators are generalized monotone and their resolvents are computable, while the other operator is cocoercive but its resolvent is missing or costly to compute. Our splitting algorithm adapts new parameters to the generalized monotonicity of the operators and, at the same time, combines appropriate forward and backward steps to guarantee convergence to a solution of the problem.

Quantum secret sharing plays an important role in quantum cryptography. In this paper, we propose a new general quantum secret sharing scheme based on access structure and monotone span program. In our scheme, the secret distributor first distributes the secret share according to the access structure, and then each participant in the authorization set hides their secret share in the qubits, and then transmits each qubit safely performed on unitary transformation. Compared with the existing quantum secret sharing schemes, our scheme is more flexible, general and less computational cost in practical applications.

We investigate the structure of $\omega$-limit (resp. $\alpha$-limit) sets for a monotone map $f$ on a regular curve $X$. %Let $X$ be a regular curve and let $f: X\longrightarrowX$ be a monotone map. We show that for any $x\in X$ (resp. for any negative orbit $(x_{n})_{n\geq 0}$ of $x$), the $\omega$-limit set $\omega_{f}(x)$ (resp. $\alpha$-limit set $\alpha_{f}((x_{n})_{n\geq 0})$) is a minimal set. This also hold for $\alpha$-limit set $\alpha_{f}(x)$ whenever $x$ is not a periodic point. These results extend those of Naghmouchi \cite{n} %[J. Difference Equ. Appl., 23 (2017), 1485--1490] established whenever $f$ is a homeomorphism on a regular curve and those of Abdelli \cite{a} %[Chaos, Solitons Fractals, 71 (2015), 66--72] , whenever $f$ is a monotone map on a local dendrite. Further results related to the basin of attraction of an infinite minimal set are also obtained., Comment: 18 pages, 1 figure

In this paper, we are concerned with a kind of tempered fractional differential equation Riemann–Stieltjes integral boundary value problems with p-Laplacian operators. By means of the sum-type mixed monotone operators fixed point theorem based on the cone $P_{h}$ P h , we obtain not only the local existence with a unique positive solution, but also construct two successively monotone iterative sequences for approximating the unique positive solution. Finally, we present an example to illustrate our main results.

In this paper, optimal bounds for arithmetic mean in terms of hyperbolic sine mean and centroidal mean, the tangent mean and centroidal mean in exponential type are established using the monotone form of L’Hospital’s rule and the criterions for the monotonicity of the quotient of power series. Based on two basic conclusions, we carefully compare them with the existing inequalities involving the four means mentioned above, and obtain a new refined inequality chain.

Vast applications of derivative-free methods to restore the blurred images in compressive sensing has become an important trend in recent years. This research, a double direction method for better image restoration is proposed. Besides this, two double direction algorithms to solve constrained monotone nonlinear equations are presented. The main idea employed in the first algorithm is to approximate the Jacobian matrix via acceleration parameter to propose an effective derivative-free method. The second algorithm involve hybridizing the scheme of the first algorithm with Picard–Mann hybrid iterative scheme. In addition, the step length is calculated using inexact line search technique. The proposed methods are proven to be globally convergent under some mild conditions . The numerical experiment, shown in this paper, depicts the efficiency of the proposed methods. Furthermore, the second method is successfully applied to handle the $$\ell _1$$ -norm regularization problem in image recovery which exhibits a better result than the existing method in the previous literature.

In this paper, first we prove the Crandall–Liggett exponential theorem in nonlinear semigroup theory on Hadamard manifolds. This theorem states that a semigroup of contractions can be constructed by the resolvent of a monotone vector field on Hadamard manifolds. Then, we show that the generated semigroup satisfies the evolution equation governed by the monotone vector field. The results of this paper are extensions of the classical results of Crandall and Liggett (Am J Math 93:265–298, 1971) and Brezis and Pazy (Israel J Math 8:367–383, 1970) to Hadamard manifolds. Some examples are also presented in the last part of the paper.

In this work we prove the uniqueness of solutions to the nonlocal linear equation $L \varphi - c(x)\varphi = 0$ in $\mathbb{R}$, where $L$ is an elliptic integro-differential operator, in the presence of a positive solution or of an odd solution vanishing only at zero. As an application, we deduce the nondegeneracy of layer solutions (bounded and monotone solutions) to the semilinear problem $L u = f(u)$ in $\mathbb{R}$ when the nonlinearity is of Allen-Cahn type. To our knowledge, this is the first work where such uniqueness and nondegeneracy results are proven in the nonlocal framework when the Caffarelli-Silvestre extension technique is not available. Our proofs are based on a nonlocal Liouville-type method developed by Hamel, Ros-Oton, Sire, and Valdinoci for nonlinear problems in dimension two., Comment: Final version to appear in Calculus of Variations and Partial Differential Equations