sum <- function(..., na.rm=FALSE) 
.Internal(sum(...,na.rm=na.rm))

min <- function(..., na.rm=FALSE) 
.Internal(min(...,na.rm=na.rm))

max <- function(..., na.rm=FALSE) 
.Internal(max(...,na.rm=na.rm))

prod <- function(...,na.rm=FALSE)
.Internal(prod(...,na.rm=na.rm))
