...final principal set...
(pJohn,keyid,y) 
(pLeague,keyid,y) 
(pMark,keyid,y) 

...final policy attribute set...
pLeague.stadium('access',true,F:pLeague.gametime(T)) <- pLeague.players(T)
pLeague.stadium('access',B:[true],F:[20120228T080000..20120228T090000]) <- pLeague.players(T)
pLeague.gametime('north') <- 20120228T130000
pLeague.gametime('south') <- 20120228T140000
pLeague.players('north') <- pJohn
pLeague.players('south') <- pMark

===good============ league.stadium(access,true,20120128T130000)<-?-john
YAP query succeed
pLeague.stadium('access',true,F:pLeague.gametime(T)) <- pLeague.players(T)
pLeague.gametime('north') <- 20120228T130000
pLeague.players('north') <- pJohn

===bad============ league.stadium(access,true,20120128T110000)<-?-mark
YAP query failed

===good============ league.stadium(access,true,20120128T080000)<-?-mark
YAP query succeed
pLeague.stadium('access',B:[true],F:[20120228T080000..20120228T090000]) <- pLeague.players(T)
pLeague.players('south') <- pMark