Lagrangian Equation

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Yu Yuan - One of the best experts on this subject based on the ideXlab platform.

Jake P. Solomon - One of the best experts on this subject based on the ideXlab platform.

  • Geodesics of positive Lagrangians from special Lagrangians with boundary
    arXiv: Symplectic Geometry, 2020
    Co-Authors: Jake P. Solomon, Amitai M. Yuval
    Abstract:

    Geodesics in the space of positive Lagrangian submanifolds are solutions of a fully non-linear degenerate elliptic PDE. We show that a geodesic segment in the space of positive Lagrangians corresponds to a one parameter family of special Lagrangian cylinders, called the cylindrical transform. The boundaries of the cylinders are contained in the positive Lagrangians at the ends of the geodesic. The special Lagrangian Equation with positive Lagrangian boundary conditions is elliptic and the solution space is a smooth manifold, which is one dimensional in the case of cylinders. A geodesic can be recovered from its cylindrical transform by solving the Dirichlet problem for the Laplace operator on each cylinder. Using the cylindrical transform, we show the space of pairs of positive Lagrangian spheres connected by a geodesic is open. Thus, we obtain the first examples of strong solutions to the geodesic Equation in arbitrary dimension not invariant under isometries. In fact, the solutions we obtain are smooth away from a finite set of points.

  • The degenerate special Lagrangian Equation
    Advances in Mathematics, 2017
    Co-Authors: Yanir A. Rubinstein, Jake P. Solomon
    Abstract:

    Abstract This article introduces the degenerate special Lagrangian Equation (DSL) and develops the basic analytic tools to construct and study its solutions. The DSL governs geodesics in the space of positive graph Lagrangians in C n . Existence of geodesics in the space of positive Lagrangians is an important step in a program for proving existence and uniqueness of special Lagrangians. Moreover, it would imply certain cases of the strong Arnold conjecture from Hamiltonian dynamics. We show the DSL is degenerate elliptic. We introduce a space–time Lagrangian angle for one-parameter families of graph Lagrangians, and construct its regularized lift. The superlevel sets of the regularized lift define subEquations for the DSL in the sense of Harvey–Lawson. We extend the existence theory of Harvey–Lawson for subEquations to the setting of domains with corners, and thus obtain solutions to the Dirichlet problem for the DSL in all branches. Moreover, we introduce the calibration measure, which plays a role similar to that of the Monge–Ampere measure in convex and complex geometry. The existence of this measure and regularity estimates allow us to prove that the solutions we obtain in the outer branches of the DSL have a well-defined length in the space of positive Lagrangians.

  • The degenerate special Lagrangian Equation
    2015
    Co-Authors: Jake P. Solomon
    Abstract:

    The degenerate special Lagrangian Equation governs geodesics in the space of positive Lagrangians. Existence of such geodesics has implications for uniqueness and existence of special Lagrangians. It also yields lower bounds on the cardinality of Lagrangian intersec- tions related to the strong Arnold conjecture. An overview of what is known about the existence problem will be given. The talk is based on joint work with A. Yuval and with Y. Rubinstein.

Yumei Zou - One of the best experts on this subject based on the ideXlab platform.

Micah Warren - One of the best experts on this subject based on the ideXlab platform.

Madhu Ramarakula - One of the best experts on this subject based on the ideXlab platform.

  • An Efficient Uplink Power Control Algorithm for LTE-Advanced Relay Networks to Improve Coverage Area
    Wireless Personal Communications, 2019
    Co-Authors: Madhu Ramarakula
    Abstract:

    Power and spectrum are limited resource, so always we needed efficient control techniques to handle them in every generation. In this paper an efficient uplink power control algorithm is proposed for LTE-Advanced relay networks to improve coverage area. It is a co-operative power control method. It is developed using the utility function concept that belongs to economic theory. This algorithm is a distributed one, which is to be set up in mobile stations operating at 3GPP LTE or LTE-Advanced relay networks. In this the Lagrangian Equation is used to solve the utility function to achieve optimal power control in the network. The outage probability analysis is carried out for the coverage area determination. It is observed that the proposed algorithm improves the cell edge user performance by maintaining the defined power levels in every mobile, improves the base station coverage area and decreases the interference level in the network.

  • An Efficient Uplink Power Control Algorithm for LTE-Advanced Relay Networks to Improve Coverage Area
    Wireless Personal Communications, 2019
    Co-Authors: Madhu Ramarakula
    Abstract:

    Power and spectrum are limited resource, so always we needed efficient control techniques to handle them in every generation. In this paper an efficient uplink power control algorithm is proposed for LTE-Advanced relay networks to improve coverage area. It is a co-operative power control method. It is developed using the utility function concept that belongs to economic theory. This algorithm is a distributed one, which is to be set up in mobile stations operating at 3GPP LTE or LTE-Advanced relay networks. In this the Lagrangian Equation is used to solve the utility function to achieve optimal power control in the network. The outage probability analysis is carried out for the coverage area determination. It is observed that the proposed algorithm improves the cell edge user performance by maintaining the defined power levels in every mobile, improves the base station coverage area and decreases the interference level in the network.