Representation of nullnorms on bounded lattices

Recently nullnorms on bounded lattices have been frequently investigated by many researchers. In this paper, we give the full characterization for quite a general class of nullnorms on bounded lattices and represent them by their underlying t-norms and t-conorms. An example is given to show the relationship between each block of the nullnorms. We also fully determine the values of arbitrary nullnorms when only one of the two variables is comparable with the absorbing elements. For the rest cases, we give some necessary conditions.