Asymptotic expansions of Laplace-type integrals. III

Laplace Asymptotic Expansions for Gaussian Functional Integrals

We obtain a Laplace asymptotic expansion, in orders of λ, of Eρx { G(λx)e −2F (λx)} } the expectation being with respect to a Gaussian process. We extend a result of Pincus [9] and build upon the previous work of Davies and Truman [1, 2, 3, 4]. Our methods differ from those of Ellis and Rosen [6, 7, 8] in that we use the supremum norm to simplify the application of the result. A.M.S. Classifica...

Asymptotic Expansions for Integrals

Asymptotic Expansions of Symmetric Standard Elliptic Integrals

Symmetric standard elliptic integrals are considered when one of their parameters is larger than the others. Distributional approach is used for deriving five convergent expansions of these integrals in inverse powers of the respective five possible asymptotic parameters. Four of these expansions involve also a logarithmic term in the asymptotic variable. Coefficients of these expansions are ob...

On the use of Hadamard expansions in hyperasymptotic evaluation of Laplace-type integrals—III: Clusters of saddle points

It is shown how the recently developed Hadamard expansion procedure can be applied to the hyperasymptotic evaluation of Laplace-type integrals containing a large variable when the phase function has a cluster of close-lying saddle points. Themodification to this procedure that is requiredwhen the saddles in the cluster coalesce to form a single higher-order saddle is discussed.An example is als...

Asymptotic Expansions of Multiple Integrals of Rapidly Oscillating Functions

Expansions of multiple integrals w(aixi,.. .,anxn)g(xi,... ,x„)dxi ■ ■ -dxn, r°i r°n I " Ja\ J a„ where w is a function on R" which is (bk oj,)-periodic in the fcth variable, k = 1,... ,n, and g is smooth, are given in terms of negative powers of the integers o\,.. .,an. Estimates of the remainder term in the expansion are also given. Introduction. Let w be a function with integrable pth power ...