"compatObjects.N" <-
function(x,y,test=FALSE){
    isValid.x <- validObject(x,test)
    isValid.y <- validObject(y,test)
    if(is.character(isValid.x))
      isValid.x
    else if(is.character(isValid.y))
      isValid.y
    else if(x@N != y@N)
      {
        compatText <- "Number of genes between objects do not agree"
        if(test)
          compatText
        else
          stop(compatText)
      }
    else
      TRUE
  }