measurable multifunction; Marczewski function; Vietoris topology; simple multifunction
We investigate the problem of approximation of measurable multifunctions by monotone sequences of measurable simple ones. Our main tool is the Marczewski function, i.e., the characteristic function of a sequence of sets.
 B. Kubiś: Approximation of measurable multifunctions
. To appear in Tatra Mt. Math. Publ. MR 1771044
 A. Kucia, A. Nowak: Approximation of Carathéodory type multifunctions
. Bull. Polish Acad. Sci. Math. 45 (1997), 187–195. MR 1466844
 E. Marczewski: The characteristic function of a sequence of sets and some of its applications. Fund. Math. 31 (1938), 207–223.
 A. Spakowski: On approximation of multifunctions with respect to the Vietoris topology
. Acta Univ. Carol. Math. Phys. 29 (1988), 75–80. MR 0983453
| Zbl 0705.54016
 A. Spakowski: On approximation by step multifunctions without compactness conditions
. Časopis Pěst. Mat. 115 (1990), 225–231. MR 1071054
| Zbl 0724.54017