| This dissertation consists of three parts.The first part studies some issues concerning the existence of non-trivial meromorphic solutions for the Fermat type functional equationF8(z)+G8(z)+H8(z)=1,and the existence of non-trivial entire solutions for the Fermat type functional equationF6(z)+G6(z)+H6(z)=1,The following results have been obtained:·There does not exist non-trivial meromorphic solutions with the exponent of conver-gence of poles is less than one satisfying the equation F8(z)+G8(z)+H8(z)=1.·There does not exist non-trivial entire solutions with the exponent of convergence of zeros is less than one satisfying the equation F6(z)+G6(z)+H6(z)=1.The second part investigates the relation between meromorphic functions and the Gauss map of complete minimal surfaces,and several classes of meromorphic functions on C were obtained which can be viewed as the Gauss map of complete minimal surfaces.This partially answers the question proposed by F.Xavier and X.L.Chao:What conditions will guarantee that the meromorphic functions in the complex plane are the Gauss map of complete minimal surfaces.The following conditions have been drawn:·Meromorphic function in the complex plane with the property that either the exponent of convergence of zeros or the exponent of convergence of poles is less than 1/2,then it must be the Gauss map of some complete minimal surface.·If g1(z)and g2(z)≠0 are entire functions which have no common zeros,at least one of the primitve functions of g12(z)and g22(z)is a composite function,which is composed of a finite numbers of entire functions with order less than 1/2,then the meromorphic function g1(z)/g2(z)can be viewed as the Gauss map of some complete minimal surface.·If g1(z)and g2(z)≠0 are entire functions which have no common zeros at least one of their Taylor expansions at the origin has 2-order Fejer gaps,then the meromorphic function g1(z)/g2(z)can be viewed as the Gauss map of some complete minimal surface.The third part discusses the uniqueness of exponential polynomials.For the special class of entitre functions,the Nevanlinna’s five-value and four-value theorem have been improved in angular domain.The following results have been proved:·Suppose f(z),g(z)are non-constant exponential polynomials and ak(k=1,2,3,4)are distinct finite complex numbers.If K≥0 and angular domains Ωk(k=1,2,3,4)of opening is larger than π,for each k ∈ {1,2},f(z)and g(z)share ak CM in the domain Dk=Ωk∩{z∈C||z|>K},and for each j ∈ {3,4},f(z)and g(z)share aj IM in the domain Dj=Ωj∩{z∈C||z|>K},then f(z)≡g(z).·Suppose f(z),g(z)are non-constant exponential polynomials and ak(k=1,2,3,4)are distinct finite complex numbers.If K>0 and angular domains Ωk(k=1,2,3)of opening is larger than π,for each k∈{1,2},f(z)and g(z)share ak CM in the domain Dk=Ωk∩{z∈C||z|>K},and f(z)and g(z)share a3 IM in the domain D3=Ω3∩{z ∈ C ||z|>K},then there exists a linear function h(z),such that h(f(z))· h(g(z))=1. |