Decomposable effectivity functions are introduced as an extension of a
dditive effectivity functions. Whereas additive effectivity functions
are determined by pairs of additive TU-games, decomposable effectivity
functions are generated by pairs of TU-games that need not be additiv
e. It turns out that the class of decomposable effectivity functions d
oes not only contain the class of additive effectivity functions but i
t also contains the class of effectivity functions corresponding to si
mple games and the class of effectivity functions corresponding to vet
o functions. We examine relations between properties of decomposable e
ffectivity functions and the TU-games by which they are generated. It
turns out that a decomposable effectivity function is stable whenever
it can be generated by a pair of balanced TU-utility games, Finally, w
e provide two characterizations of decomposable effectivity functions.
(C) 1997 Elsevier Science B.V.