???? ??? ?? ????? ???? ??????. ??? ???, ?????????? vanishing ???????, ?? ??? {????|???|??]. ???? ??????? - ???? ???? ?? {??? ??? ????, ?? ??????? ?????? ???? . ?? ??? ???? ?????? ????? , {???? ???? ?? ???? . ??? ???? ???! ????? ?- ???? ?????? ???? ?????? ??? ?????? . ??????? ?????? ?????? ??????? ??? ??? ??? ?????? ????? ?? ????? ?