The paper deals with fuzzifications of the coalitional game models in which
the expected pay-offs of players and coalitions are known only vaguely. Th
ere exists a class of games, here we call them linear coalitional games, wh
ich can be modelled as games with, as well as without, side payments. In th
e deterministic case both types of models of a linear coalitional game lead
to the same results. As the fuzzification of games with side-payments is b
ased on other principles than the fuzzification of more general games witho
ut side-payments, the linear coalitional games offer situations in which bo
th approaches to the fuzzification of coalitional game models can be compar
ed and their differences can be clearly illustrated. In this paper the atte
ntion is focused to the analysis of concepts of superadditivity and core of
coalitional games.