There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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Convex Analysisの二,三の進展について

Finite-time stability is defined for equilibria of continuous but non-Lipschitzian autonomous systems. Continuity, Lipschitz continuity, and Holder continuity of the settling-time function are studied and illustrated with several examples. Lyapunov and converse Lyapunov results involving scalar differential inequalities are given for finite-time stability. It is shown that the regularity properties of the Lyapunov function and those of the settling-time function are related. Consequently, converse Lyapunov results can only assure the existence of continuous Lyapunov functions. Finally, the sensitivity of finite-time-stable systems to perturbations is investigated.

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Finite-Time Stability of Continuous Autonomous Systems

Fractional Differential Equations

to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.

Linear and nonlinear waves, by G. B. Whitham. Pp.636. £50. 1999. ISBN 0 471 35942 4 (Wiley).

Stability analysis of fractional differential system with Riemann-Liouville derivative

The heat equation also shows what a PDE is in general: We are given some kind of relationship between a function u(x,t) and/or its partial derivatives. In the one dimensional case this can be partial derivatives in time t or in space x. The problem is to find functions u(x,t) which satisfy the given relationship and sometimes satisfy additional conditions (initital value conditions or boundary conditions).

The One-Dimensional Heat Equation

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On fourth order boundary value problems arising in beam analysis

We employ the critical point theory to establish the existence of multiple solutions of some regular as well as singular discrete boundary value problems. ? 2004 Elsevier Ltd. All rights reserved. MSC: 34B16; 39A10

Multiple positive solutions of singular and nonsingular discrete problems via variational methods

1. Introduction to Oscillation Theory.- 2. Scalar Delay Differential Equations on Semiaxes.- 3. Scalar Delay Differential Equations on Semiaxis with Positive and Negative Coefficients.- 4. Oscillation of Equations with a Distributed Delay.- 5. Scalar Advanced and Mixed Differential Equations on Semiaxes.- 6. Neutral Differential Equations.- 7. Second Order Delay Differential Equations.- 8. Second Order Delay Differential Equations with Damping Terms.- 9. Vector Delay Differential Equations.- 10. Linearized Methods for Nonlinear Equations with a Distributed Delay.- 11. Nonlinear Models - Modifications of Delay Logistic Equations.- 12. First Order Linear Delay Impulsive Differential Equation.- 13. Second Order Linear Delay Impulsive Differential Equations.- 14. Linearized Oscillation Theory for Nonlinear Delay Impulsive Equations.- 15. Maximum Principles and Nonoscillation Intervals for First Order Volterra Functional Differential Equations.- 16. Systems of Functional Differential Equations on Finite Intervals.- 17. Nonoscillation Interval for n-th Order Functional Differential Equations.- Appendix A.- Appendix B.

https://www.math.bgu.ac.il/~brznsky/Front%20matter_book.pdf

Ravi P. Agarwal

Papers

Stability analysis of fractional differential system with Riemann-Liouville derivative

The One-Dimensional Heat Equation

On fourth order boundary value problems arising in beam analysis

Multiple positive solutions of singular and nonsingular discrete problems via variational methods

Nonoscillation Theory of Functional Differential Equations with Applications