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Aerodynamic coefficients. --- Commercial aircraft. --- Energy consumption. --- Fuel consumption. --- Aerodynamic drag. --- Induced drag.
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Aerodynamic coefficients. --- Aerodynamic characteristics. --- Aeroelasticity. --- Flight tests. --- Flutter analysis. --- Influence coefficient. --- Prediction analysis techniques. --- Unsteady aerodynamics.
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Matrices (mathematics) --- Transonic flow. --- Aerodynamic coefficients. --- Design optimization. --- Approximation. --- Flutter analysis. --- Influence coefficient. --- Prediction analysis techniques. --- Unsteady aerodynamics.
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"Modular forms are tremendously important in various areas of mathematics, from number theory and algebraic geometry to combinatorics and lattices. Their Fourier coefficients, with Ramanujan's tau-function as a typical example, have deep arithmetic significance. Prior to this book, the fastest known algorithms for computing these Fourier coefficients took exponential time, except in some special cases. The case of elliptic curves (Schoof's algorithm) was at the birth of elliptic curve cryptography around 1985. This book gives an algorithm for computing coefficients of modular forms of level one in polynomial time. For example, Ramanujan's tau of a prime number P can be computed in time bounded by a fixed power of the logarithm of P. Such fast computation of Fourier coefficients is itself based on the main result of the book: the computation, in polynomial time, of Galois representations over finite fields attached to modular forms by the Langlands program. Because these Galois representations typically have a nonsolvable image, this result is a major step forward from explicit class field theory, and it could be described as the start of the explicit Langlands program. The computation of the Galois representations uses their realization, following Shimura and Deligne, in the torsion subgroup of Jacobian varieties of modular curves. The main challenge is then to perform the necessary computations in time polynomial in the dimension of these highly nonlinear algebraic varieties. Exact computations involving systems of polynomial equations in many variables take exponential time. This is avoided by numerical approximations with a precision that suffices to derive exact results from them. Bounds for the required precision--in other words, bounds for the height of the rational numbers that describe the Galois representation to be computed--are obtained from Arakelov theory. Two types of approximations are treated: one using complex uniformization and another one using geometry over finite fields. The book begins with a concise and concrete introduction that makes its accessible to readers without an extensive background in arithmetic geometry. And the book includes a chapter that describes actual computations"-- "This book represents a major step forward from explicit class field theory, and it could be described as the start of the 'explicit Langlands program'"--
Galois modules (Algebra) --- Class field theory. --- Algebraic number theory --- Galois module structure (Algebra) --- Galois's modules (Algebra) --- Modules (Algebra) --- Arakelov invariants. --- Arakelov theory. --- Fourier coefficients. --- Galois representation. --- Galois representations. --- Green functions. --- Hecke operators. --- Jacobians. --- Langlands program. --- Las Vegas algorithm. --- Lehmer. --- Peter Bruin. --- Ramanujan's tau function. --- Ramanujan's tau-function. --- Ramanujan's tau. --- Riemann surfaces. --- Schoof's algorithm. --- Turing machines. --- algorithms. --- arithmetic geometry. --- arithmetic surfaces. --- bounding heights. --- bounds. --- coefficients. --- complex roots. --- computation. --- computing algorithms. --- computing coefficients. --- cusp forms. --- cuspidal divisor. --- eigenforms. --- finite fields. --- height functions. --- inequality. --- lattices. --- minimal polynomial. --- modular curves. --- modular forms. --- modular representation. --- modular representations. --- modular symbols. --- nonvanishing conjecture. --- p-adic methods. --- plane curves. --- polynomial time algorithm. --- polynomial time algoriths. --- polynomial time. --- polynomials. --- power series. --- probabilistic polynomial time. --- random divisors. --- residual representation. --- square root. --- square-free levels. --- tale cohomology. --- torsion divisors. --- torsion.
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This book was written for researchers and engineers working with aerial and underwater acoustics. It examines the interactions of acoustic waves with obstacles that may be rigid, soft, elastic, or characterized by an impedance boundary condition. The approach is founded on asymptotic high-frequency diffraction methods based on the concept of rays. Despite the progress in the field of numerical methods for diffraction problems, ray methods remain the most useful approximate methods for analyzing wave motions. Ray methods provide considerable physical insight into diffraction mechanisms and allow for the analytic treatment of objects that are still too large in terms of wavelength to be solved in the realm of numerical methods.
Sound-waves --- Vibration --- Waves --- Diffraction --- Mathematical models. --- Aerial acoustics --- Underwater acoustics --- Asymptotic expansions --- Acoustic waves --- Impedance boundary conditions --- Canonical problems --- Creeping waves --- Elastic surface waves --- Whispering gallery modes --- Maliuzhinets's diffraction coefficient --- Uniform asymptotic theory --- Field near a caustic --- Hybrid diffraction coefficients
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