On oscillatory integrals associated to phase functions with degenerate singular points

Abstract

In this note, by using the result in one variable, we obtain asymptotic expansions of oscillatory integrals for certain multivariable phase functions with {\bf degenerate} singular points. Moreover by using this result, we have asymptotic expansions of oscillatory integrals with phase function of type $A_k$, $E_6$, $E_8$-function germs.