P adic gamma function

In mathematics, the p-adic gamma function Γ_p(s) is a function of a p-adic variable s analogous to the gamma function. It was first explicitly defined by Morita (1975), though Boyarsky (1980) pointed out that Dwork (1964) implicitly used the same function. Diamond (1977) defined a p-adic analog G_p(s) of log Γ(s). Overholtzer (1952) had previously given a definition of a different p-adic analogue of the gamma function, but his function does not have satisfactory properties and is not used much.