标题: 什麽是形式集合Formal Sets/PowerFormalSet？ [打印本页] 作者: lilianjie 时间: 2011-12-30 12:18 标题: 什麽是形式集合Formal Sets/PowerFormalSet？ 哪位能给理解下： 3 W; A* @2 |9 D9 g 7 h/ `( S. ~$ a( l: e( T. {- T6 HFormal Sets " ~7 W9 J8 E( Q4 TA formal set consists of the subset of elements of some carrier set (structure) on which a certain predicate assumes the value `true'. " m9 m5 n) j& J$ A* r- O- v! V
9 i) ~; F @& a5 }; W( O p2 F' e0 V! jThe only set-theoretic operations that can be performed on formal sets are union, intersection, difference and symmetric difference, and element membership testing. 9 c6 S% {2 r- T6 B, A' d
) C/ e. [: n' j - p7 q) J! {, n* ]. ? 5 q' g2 p0 q% c4 BS := { 1 .. 5}; / Z6 M, |9 K* V# O8 a9 z/ l4 T> P := PowerSet(S);7 P3 T1 f! F3 j
P;/ t; l2 ~/ }1 l1 @- C! P7 w9 G8 Z
PFS:=PowerFormalSet(S); ! L0 N$ E; n" N+ n& F# kPFS; / ]( @4 r2 E0 I1 t7 u+ p2 iF := { 2, 4 };4 R- R! Q/ ~4 c3 o: G/ s
FF := { 2/3, 4 }; j- u$ n* V! i8 M& l
! N1 \2 ^6 c' X0 s' m
F in P; 1 k0 ?5 A& y Q, RFF in P;" @: L4 ]) d4 v
F in PFS;' i6 B6 L3 T6 p9 P
FF in PFS;. w- d6 l. b! o/ Q- z2 ]) S
Set of subsets of { 1 .. 5 }+ E! _: v; q1 I9 [
Set of formal subsets of { 1 .. 5 } ' ?5 g7 r, P2 X$ o' f+ C: ntrue 8 s+ D) t1 r$ W) [false" Q8 p% P% T W ^
; ]4 N" s& u" u& E" V) y7 G; F; {
>> F in PFS; $ S, U7 |2 y: L( L6 b" l ^ ) P4 N* j& S% h" U. R; eRuntime error in 'in': Bad argument types : Z4 E. w# `/ R( a 4 x |0 E8 J$ O, j+ i; A9 k ^3 R f0 T9 A) H* {" z
>> FF in PFS;+ H! D. F1 c. l3 w/ G, s# z0 ?1 J
^9 I. }8 M( _7 @) K3 n9 B
Runtime error in 'in': Bad argument types