Copyright (c) 2003 Association of Mizar Users
environ vocabulary MEMBERED, XCMPLX_0, ARYTM, INT_1, ORDINAL2, BOOLE, COMPLEX1, RAT_1, ORDINAL1, TARSKI, SETFAM_1; notation TARSKI, XBOOLE_0, ENUMSET1, SUBSET_1, SETFAM_1, NUMBERS, XCMPLX_0, XREAL_0, RAT_1, INT_1, ORDINAL1, ORDINAL2; constructors XCMPLX_0, RAT_1, ENUMSET1, SETFAM_1; clusters INT_1, NUMBERS, ARYTM_3, XREAL_0, RAT_1, XBOOLE_0; requirements NUMERALS, BOOLE, SUBSET; definitions XCMPLX_0, XREAL_0, INT_1, TARSKI, RAT_1, XBOOLE_0; theorems INT_1, ORDINAL2, XBOOLE_0, XREAL_0, XCMPLX_0, RAT_1, SUBSET_1, ORDINAL1, TARSKI, ENUMSET1, XBOOLE_1, SETFAM_1, NUMBERS; schemes XBOOLE_0; begin Lm1: 1 = succ 0 .= 0 \/ {0} by ORDINAL1:def 1 .= {0}; reserve x, X, F for set; definition let X be set; attr X is complex-membered means :Def1: x in X implies x is complex; attr X is real-membered means :Def2: x in X implies x is real; attr X is rational-membered means :Def3: x in X implies x is rational; attr X is integer-membered means :Def4: x in X implies x is integer; attr X is natural-membered means :Def5: x in X implies x is natural; end; definition cluster natural-membered -> integer-membered set; coherence proof let X; assume A1: X is natural-membered; let x; assume x in X; then x is natural by A1,Def5; then x in omega by ORDINAL2:def 21; hence x is Element of INT by INT_1:14; end; cluster integer-membered -> rational-membered set; coherence proof let X; assume A2: X is integer-membered; let x; assume x in X; then x is integer by A2,Def4; then x is Element of INT by INT_1:def 2; then x in INT; hence x in RAT by RAT_1:11; end; cluster rational-membered -> real-membered set; coherence proof let X; assume A3: X is rational-membered; let x; assume x in X; then x is rational by A3,Def3; then x in RAT by RAT_1:def 2; hence x in REAL by RAT_1:4; end; cluster real-membered -> complex-membered set; coherence proof let X; assume A4: X is real-membered; let x; assume x in X; then x is real by A4,Def2; then x in REAL by XREAL_0:def 1; hence x in COMPLEX by NUMBERS:11; end; end; definition cluster non empty natural-membered set; existence proof take 1; thus 1 is non empty; let x; assume x in 1; hence thesis by Lm1,TARSKI:def 1; end; end; definition cluster -> complex-membered Subset of COMPLEX; coherence proof let S be Subset of COMPLEX; let x; assume x in S; hence x is complex by XCMPLX_0:def 2; end; cluster -> real-membered Subset of REAL; coherence proof let S be Subset of REAL; let x; thus thesis by XREAL_0:def 1; end; cluster -> rational-membered Subset of RAT; coherence proof let S be Subset of RAT; let x; thus thesis by RAT_1:def 2; end; cluster -> integer-membered Subset of INT; coherence proof let S be Subset of INT; let x; thus thesis by INT_1:def 2; end; cluster -> natural-membered Subset of NAT; coherence proof let S be Subset of NAT; let x; thus thesis by ORDINAL2:def 21; end; end; definition cluster COMPLEX -> complex-membered; coherence proof let x; thus thesis by XCMPLX_0:def 2; end; cluster REAL -> real-membered; coherence proof let x; thus thesis by XREAL_0:def 1; end; cluster RAT -> rational-membered; coherence proof let x; thus thesis by RAT_1:def 2; end; cluster INT -> integer-membered; coherence proof let x; thus thesis by INT_1:def 2; end; cluster NAT -> natural-membered; coherence proof let x; thus thesis by ORDINAL2:def 21; end; end; theorem Th1: X is complex-membered implies X c= COMPLEX proof assume A1: X is complex-membered; let x; assume x in X; then x is complex by A1,Def1; hence x in COMPLEX by XCMPLX_0:def 2; end; theorem Th2: X is real-membered implies X c= REAL proof assume A1: X is real-membered; let x; assume x in X; then x is real by A1,Def2; hence x in REAL by XREAL_0:def 1; end; theorem Th3: X is rational-membered implies X c= RAT proof assume A1: X is rational-membered; let x; assume x in X; then x is rational by A1,Def3; hence x in RAT by RAT_1:def 2; end; theorem Th4: X is integer-membered implies X c= INT proof assume A1: X is integer-membered; let x; assume x in X; then x is integer by A1,Def4; then x is Element of INT by INT_1:def 2; hence x in INT; end; theorem Th5: X is natural-membered implies X c= NAT proof assume A1: X is natural-membered; let x; assume x in X; then x is natural by A1,Def5; hence x in NAT by ORDINAL2:def 21; end; definition let X be complex-membered set; cluster -> complex Element of X; coherence proof let e be Element of X; per cases; suppose X is empty; then e = 0 by SUBSET_1:def 2; hence e is complex; suppose X is non empty; hence e is complex by Def1; end; end; definition let X be real-membered set; cluster -> real Element of X; coherence proof let e be Element of X; per cases; suppose X is empty; then e = 0 by SUBSET_1:def 2; hence e is real; suppose X is non empty; hence e is real by Def2; end; end; definition let X be rational-membered set; cluster -> rational Element of X; coherence proof let e be Element of X; per cases; suppose X is empty; then e = 0 by SUBSET_1:def 2; then e is Element of INT by INT_1:def 2; then e in INT; hence e is rational by RAT_1:11,def 2; suppose X is non empty; hence e is rational by Def3; end; end; definition let X be integer-membered set; cluster -> integer Element of X; coherence proof let e be Element of X; per cases; suppose X is empty; then e = 0 by SUBSET_1:def 2; hence e is integer; suppose X is non empty; hence e is integer by Def4; end; end; definition let X be natural-membered set; cluster -> natural Element of X; coherence proof let e be Element of X; per cases; suppose X is empty; then e = 0 by SUBSET_1:def 2; hence e is natural; suppose X is non empty; hence e is natural by Def5; end; end; reserve c, c1, c2, c3 for complex number, r, r1, r2, r3 for real number, w, w1, w2, w3 for rational number, i, i1, i2, i3 for integer number, n, n1, n2, n3 for natural number; theorem for X being non empty complex-membered set ex c st c in X proof let X be non empty complex-membered set; consider x being set such that A1: x in X by XBOOLE_0:def 1; x is complex number by A1,Def1; hence thesis by A1; end; theorem for X being non empty real-membered set ex r st r in X proof let X be non empty real-membered set; consider x being set such that A1: x in X by XBOOLE_0:def 1; x is real number by A1,Def2; hence thesis by A1; end; theorem for X being non empty rational-membered set ex w st w in X proof let X be non empty rational-membered set; consider x being set such that A1: x in X by XBOOLE_0:def 1; x is rational number by A1,Def3; hence thesis by A1; end; theorem for X being non empty integer-membered set ex i st i in X proof let X be non empty integer-membered set; consider x being set such that A1: x in X by XBOOLE_0:def 1; x is integer number by A1,Def4; hence thesis by A1; end; theorem for X being non empty natural-membered set ex n st n in X proof let X be non empty natural-membered set; consider x being set such that A1: x in X by XBOOLE_0:def 1; x is natural number by A1,Def5; hence thesis by A1; end; theorem for X being complex-membered set st for c holds c in X holds X = COMPLEX proof let X be complex-membered set such that A1: for c holds c in X; thus X c= COMPLEX by Th1; let e be set; assume e in COMPLEX; then e is complex by XCMPLX_0:def 2; hence e in X by A1; end; theorem for X being real-membered set st for r holds r in X holds X = REAL proof let X be real-membered set such that A1: for r holds r in X; thus X c= REAL by Th2; let e be set; assume e in REAL; then e is real by XREAL_0:def 1; hence e in X by A1; end; theorem for X being rational-membered set st for w holds w in X holds X = RAT proof let X be rational-membered set such that A1: for w holds w in X; thus X c= RAT by Th3; let e be set; assume e in RAT; then e is rational by RAT_1:def 2; hence e in X by A1; end; theorem for X being integer-membered set st for i holds i in X holds X = INT proof let X be integer-membered set such that A1: for i holds i in X; thus X c= INT by Th4; let e be set; assume e in INT; then e is integer by INT_1:def 2; hence e in X by A1; end; theorem for X being natural-membered set st for n holds n in X holds X = NAT proof let X be natural-membered set such that A1: for n holds n in X; thus X c= NAT by Th5; let e be set; assume e in NAT; then e is natural by ORDINAL2:def 21; hence e in X by A1; end; theorem Th16: for Y being complex-membered set st X c= Y holds X is complex-membered proof let Y be complex-membered set such that A1: X c= Y; let x; thus thesis by A1,Def1; end; theorem Th17: for Y being real-membered set st X c= Y holds X is real-membered proof let Y be real-membered set such that A1: X c= Y; let x; thus thesis by A1,Def2; end; theorem Th18: for Y being rational-membered set st X c= Y holds X is rational-membered proof let Y be rational-membered set such that A1: X c= Y; let x; thus thesis by A1,Def3; end; theorem Th19: for Y being integer-membered set st X c= Y holds X is integer-membered proof let Y be integer-membered set such that A1: X c= Y; let x; thus thesis by A1,Def4; end; theorem Th20: for Y being natural-membered set st X c= Y holds X is natural-membered proof let Y be natural-membered set such that A1: X c= Y; let x; thus thesis by A1,Def5; end; definition cluster {} -> natural-membered; coherence proof let x; thus thesis; end; end; definition cluster empty -> natural-membered set; coherence; end; definition let c; cluster {c} -> complex-membered; coherence proof let e be set; thus thesis by TARSKI:def 1; end; end; definition let r; cluster {r} -> real-membered; coherence proof let e be set; thus thesis by TARSKI:def 1; end; end; definition let w; cluster {w} -> rational-membered; coherence proof let e be set; thus thesis by TARSKI:def 1; end; end; definition let i; cluster {i} -> integer-membered; coherence proof let e be set; thus thesis by TARSKI:def 1; end; end; definition let n; cluster {n} -> natural-membered; coherence proof let e be set; thus thesis by TARSKI:def 1; end; end; definition let c1,c2; cluster {c1,c2} -> complex-membered; coherence proof let e be set; thus thesis by TARSKI:def 2; end; end; definition let r1,r2; cluster {r1,r2} -> real-membered; coherence proof let e be set; thus thesis by TARSKI:def 2; end; end; definition let w1,w2; cluster {w1,w2} -> rational-membered; coherence proof let e be set; thus thesis by TARSKI:def 2; end; end; definition let i1,i2; cluster {i1,i2} -> integer-membered; coherence proof let e be set; thus thesis by TARSKI:def 2; end; end; definition let n1,n2; cluster {n1,n2} -> natural-membered; coherence proof let e be set; thus thesis by TARSKI:def 2; end; end; definition let c1,c2,c3; cluster {c1,c2,c3} -> complex-membered; coherence proof let e be set; thus thesis by ENUMSET1:def 1; end; end; definition let r1,r2,r3; cluster {r1,r2,r3} -> real-membered; coherence proof let e be set; thus thesis by ENUMSET1:def 1; end; end; definition let w1,w2,w3; cluster {w1,w2,w3} -> rational-membered; coherence proof let e be set; thus thesis by ENUMSET1:def 1; end; end; definition let i1,i2,i3; cluster {i1,i2,i3} -> integer-membered; coherence proof let e be set; thus thesis by ENUMSET1:def 1; end; end; definition let n1,n2,n3; cluster {n1,n2,n3} -> natural-membered; coherence proof let e be set; thus thesis by ENUMSET1:def 1; end; end; definition let X be complex-membered set; cluster -> complex-membered Subset of X; coherence proof let S be Subset of X, x; thus thesis by Def1; end; end; definition let X be real-membered set; cluster -> real-membered Subset of X; coherence proof let S be Subset of X, x; thus thesis by Def2; end; end; definition let X be rational-membered set; cluster -> rational-membered Subset of X; coherence proof let S be Subset of X, x; thus thesis by Def3; end; end; definition let X be integer-membered set; cluster -> integer-membered Subset of X; coherence proof let S be Subset of X, x; thus thesis by Def4; end; end; definition let X be natural-membered set; cluster -> natural-membered Subset of X; coherence proof let S be Subset of X, x; thus thesis by Def5; end; end; definition let X,Y be complex-membered set; cluster X \/ Y -> complex-membered; coherence proof let x; assume x in X \/ Y; then x in X or x in Y by XBOOLE_0:def 2; hence thesis by Def1; end; end; definition let X,Y be real-membered set; cluster X \/ Y -> real-membered; coherence proof let x; assume x in X \/ Y; then x in X or x in Y by XBOOLE_0:def 2; hence thesis by Def2; end; end; definition let X,Y be rational-membered set; cluster X \/ Y -> rational-membered; coherence proof let x; assume x in X \/ Y; then x in X or x in Y by XBOOLE_0:def 2; hence thesis by Def3; end; end; definition let X,Y be integer-membered set; cluster X \/ Y -> integer-membered; coherence proof let x; assume x in X \/ Y; then x in X or x in Y by XBOOLE_0:def 2; hence thesis by Def4; end; end; definition let X,Y be natural-membered set; cluster X \/ Y -> natural-membered; coherence proof let x; assume x in X \/ Y; then x in X or x in Y by XBOOLE_0:def 2; hence thesis by Def5; end; end; definition let X be complex-membered set, Y be set; cluster X /\ Y -> complex-membered; coherence proof X /\ Y c= X by XBOOLE_1:17; hence thesis by Th16; end; cluster Y /\ X -> complex-membered; coherence proof Y /\ X c= X by XBOOLE_1:17; hence thesis by Th16; end; end; definition let X be real-membered set, Y be set; cluster X /\ Y -> real-membered; coherence proof X /\ Y c= X by XBOOLE_1:17; hence thesis by Th17; end; cluster Y /\ X -> real-membered; coherence proof Y /\ X c= X by XBOOLE_1:17; hence thesis by Th17; end; end; definition let X be rational-membered set, Y be set; cluster X /\ Y -> rational-membered; coherence proof X /\ Y c= X by XBOOLE_1:17; hence thesis by Th18; end; cluster Y /\ X -> rational-membered; coherence proof Y /\ X c= X by XBOOLE_1:17; hence thesis by Th18; end; end; definition let X be integer-membered set, Y be set; cluster X /\ Y -> integer-membered; coherence proof X /\ Y c= X by XBOOLE_1:17; hence thesis by Th19; end; cluster Y /\ X -> integer-membered; coherence proof Y /\ X c= X by XBOOLE_1:17; hence thesis by Th19; end; end; definition let X be natural-membered set, Y be set; cluster X /\ Y -> natural-membered; coherence proof X /\ Y c= X by XBOOLE_1:17; hence thesis by Th20; end; cluster Y /\ X -> natural-membered; coherence proof Y /\ X c= X by XBOOLE_1:17; hence thesis by Th20; end; end; definition let X be complex-membered set, Y be set; cluster X \ Y -> complex-membered; coherence proof X \ Y c= X by XBOOLE_1:36; hence thesis by Th16; end; end; definition let X be real-membered set, Y be set; cluster X \ Y -> real-membered; coherence proof X \ Y c= X by XBOOLE_1:36; hence thesis by Th17; end; end; definition let X be rational-membered set, Y be set; cluster X \ Y -> rational-membered; coherence proof X \ Y c= X by XBOOLE_1:36; hence thesis by Th18; end; end; definition let X be integer-membered set, Y be set; cluster X \ Y -> integer-membered; coherence proof X \ Y c= X by XBOOLE_1:36; hence thesis by Th19; end; end; definition let X be natural-membered set, Y be set; cluster X \ Y -> natural-membered; coherence proof X \ Y c= X by XBOOLE_1:36; hence thesis by Th20; end; end; definition let X,Y be complex-membered set; cluster X \+\ Y -> complex-membered; coherence proof X \+\ Y = (X \ Y) \/ (Y \ X) by XBOOLE_0:def 6; hence thesis; end; end; definition let X,Y be real-membered set; cluster X \+\ Y -> real-membered; coherence proof X \+\ Y = (X \ Y) \/ (Y \ X) by XBOOLE_0:def 6; hence thesis; end; end; definition let X,Y be rational-membered set; cluster X \+\ Y -> rational-membered; coherence proof X \+\ Y = (X \ Y) \/ (Y \ X) by XBOOLE_0:def 6; hence thesis; end; end; definition let X,Y be integer-membered set; cluster X \+\ Y -> integer-membered; coherence proof X \+\ Y = (X \ Y) \/ (Y \ X) by XBOOLE_0:def 6; hence thesis; end; end; definition let X,Y be natural-membered set; cluster X \+\ Y -> natural-membered; coherence proof X \+\ Y = (X \ Y) \/ (Y \ X) by XBOOLE_0:def 6; hence thesis; end; end; definition let X,Y be complex-membered set; redefine pred X c= Y means :Def6: c in X implies c in Y; compatibility proof thus X c= Y implies for c st c in X holds c in Y; assume A1: c in X implies c in Y; let x; assume A2: x in X; then x is complex by Def1; hence thesis by A1,A2; end; end; definition let X,Y be real-membered set; redefine pred X c= Y means :Def7: r in X implies r in Y; compatibility proof thus X c= Y implies for r st r in X holds r in Y; assume A1: r in X implies r in Y; let c; assume A2: c in X; then c is real by Def2; hence thesis by A1,A2; end; end; definition let X,Y be rational-membered set; redefine pred X c= Y means :Def8: w in X implies w in Y; compatibility proof thus X c= Y implies for w st w in X holds w in Y; assume A1: w in X implies w in Y; let r; assume A2: r in X; then r is rational by Def3; hence thesis by A1,A2; end; end; definition let X,Y be integer-membered set; redefine pred X c= Y means :Def9: i in X implies i in Y; compatibility proof thus X c= Y implies for i st i in X holds i in Y; assume A1: i in X implies i in Y; let w; assume A2: w in X; then w is integer by Def4; hence thesis by A1,A2; end; end; definition let X,Y be natural-membered set; redefine pred X c= Y means :Def10: n in X implies n in Y; compatibility proof thus X c= Y implies for n st n in X holds n in Y; assume A1: n in X implies n in Y; let i; assume A2: i in X; then i is natural by Def5; hence thesis by A1,A2; end; end; definition let X,Y be complex-membered set; redefine pred X = Y means c in X iff c in Y; compatibility proof thus X = Y implies for c holds c in X iff c in Y; assume c in X iff c in Y; hence X c= Y & Y c= X by Def6; end; end; definition let X,Y be real-membered set; redefine pred X = Y means r in X iff r in Y; compatibility proof thus X = Y implies for r holds r in X iff r in Y; assume r in X iff r in Y; then X c= Y & Y c= X by Def7; hence thesis by XBOOLE_0:def 10; end; end; definition let X,Y be rational-membered set; redefine pred X = Y means w in X iff w in Y; compatibility proof thus X = Y implies for w holds w in X iff w in Y; assume w in X iff w in Y; then X c= Y & Y c= X by Def8; hence thesis by XBOOLE_0:def 10; end; end; definition let X,Y be integer-membered set; redefine pred X = Y means i in X iff i in Y; compatibility proof thus X = Y implies for i holds i in X iff i in Y; assume i in X iff i in Y; then X c= Y & Y c= X by Def9; hence thesis by XBOOLE_0:def 10; end; end; definition let X,Y be natural-membered set; redefine pred X = Y means n in X iff n in Y; compatibility proof thus X = Y implies for n holds n in X iff n in Y; assume n in X iff n in Y; then X c= Y & Y c= X by Def10; hence thesis by XBOOLE_0:def 10; end; end; definition let X,Y be complex-membered set; redefine pred X meets Y means ex c st c in X & c in Y; compatibility proof thus X misses Y implies not ex c st c in X & c in Y by XBOOLE_0:3; assume A1: not ex c st c in X & c in Y; assume X meets Y; then consider x such that A2: x in X & x in Y by XBOOLE_0:3; x is complex by A2,Def1; hence thesis by A1,A2; end; end; definition let X,Y be real-membered set; redefine pred X meets Y means ex r st r in X & r in Y; compatibility proof thus X misses Y implies not ex r st r in X & r in Y by XBOOLE_0:3; assume A1: not ex r st r in X & r in Y; assume X meets Y; then consider x such that A2: x in X & x in Y by XBOOLE_0:3; x is real by A2,Def2; hence thesis by A1,A2; end; end; definition let X,Y be rational-membered set; redefine pred X meets Y means ex w st w in X & w in Y; compatibility proof thus X misses Y implies not ex w st w in X & w in Y by XBOOLE_0:3; assume A1: not ex w st w in X & w in Y; assume X meets Y; then consider x such that A2: x in X & x in Y by XBOOLE_0:3; x is rational by A2,Def3; hence thesis by A1,A2; end; end; definition let X,Y be integer-membered set; redefine pred X meets Y means ex i st i in X & i in Y; compatibility proof thus X misses Y implies not ex i st i in X & i in Y by XBOOLE_0:3; assume A1: not ex i st i in X & i in Y; assume X meets Y; then consider x such that A2: x in X & x in Y by XBOOLE_0:3; x is integer by A2,Def4; hence thesis by A1,A2; end; end; definition let X,Y be natural-membered set; redefine pred X meets Y means ex n st n in X & n in Y; compatibility proof thus X misses Y implies not ex n st n in X & n in Y by XBOOLE_0:3; assume A1: not ex n st n in X & n in Y; assume X meets Y; then consider x such that A2: x in X & x in Y by XBOOLE_0:3; x is natural by A2,Def5; hence thesis by A1,A2; end; end; theorem (for X st X in F holds X is complex-membered) implies union F is complex-membered proof assume A1: for X st X in F holds X is complex-membered; let x; assume x in union F; then consider X such that A2: x in X and A3: X in F by TARSKI:def 4; X is complex-membered by A1,A3; hence x is complex by A2,Def1; end; theorem (for X st X in F holds X is real-membered) implies union F is real-membered proof assume A1: for X st X in F holds X is real-membered; let x; assume x in union F; then consider X such that A2: x in X and A3: X in F by TARSKI:def 4; X is real-membered by A1,A3; hence x is real by A2,Def2; end; theorem (for X st X in F holds X is rational-membered) implies union F is rational-membered proof assume A1: for X st X in F holds X is rational-membered; let x; assume x in union F; then consider X such that A2: x in X and A3: X in F by TARSKI:def 4; X is rational-membered by A1,A3; hence x is rational by A2,Def3; end; theorem (for X st X in F holds X is integer-membered) implies union F is integer-membered proof assume A1: for X st X in F holds X is integer-membered; let x; assume x in union F; then consider X such that A2: x in X and A3: X in F by TARSKI:def 4; X is integer-membered by A1,A3; hence x is integer by A2,Def4; end; theorem (for X st X in F holds X is natural-membered) implies union F is natural-membered proof assume A1: for X st X in F holds X is natural-membered; let x; assume x in union F; then consider X such that A2: x in X and A3: X in F by TARSKI:def 4; X is natural-membered by A1,A3; hence x is natural by A2,Def5; end; theorem for X st X in F & X is complex-membered holds meet F is complex-membered proof let X; assume X in F; then meet F c= X by SETFAM_1:4; hence thesis by Th16; end; theorem for X st X in F & X is real-membered holds meet F is real-membered proof let X; assume X in F; then meet F c= X by SETFAM_1:4; hence thesis by Th17; end; theorem for X st X in F & X is rational-membered holds meet F is rational-membered proof let X; assume X in F; then meet F c= X by SETFAM_1:4; hence thesis by Th18; end; theorem for X st X in F & X is integer-membered holds meet F is integer-membered proof let X; assume X in F; then meet F c= X by SETFAM_1:4; hence thesis by Th19; end; theorem for X st X in F & X is natural-membered holds meet F is natural-membered proof let X; assume X in F; then meet F c= X by SETFAM_1:4; hence thesis by Th20; end; scheme CM_Separation {P[set]}: ex X being complex-membered set st for c holds c in X iff P[c] proof defpred _P[set] means P[$1]; consider X being set such that A1: x in X iff x in COMPLEX & _P[x] from Separation; X is complex-membered proof let x; assume x in X; then x in COMPLEX by A1; hence thesis by XCMPLX_0:def 2; end; then reconsider X as complex-membered set; take X; let c; c in COMPLEX by XCMPLX_0:def 2; hence thesis by A1; end; scheme RM_Separation {P[set]}: ex X being real-membered set st for r holds r in X iff P[r] proof defpred _P[set] means P[$1]; consider X being set such that A1: x in X iff x in REAL & _P[x] from Separation; X is real-membered proof let x; assume x in X; then x in REAL by A1; hence thesis by XREAL_0:def 1; end; then reconsider X as real-membered set; take X; let r; r in REAL by XREAL_0:def 1; hence thesis by A1; end; scheme WM_Separation {P[set]}: ex X being rational-membered set st for w holds w in X iff P[w] proof defpred _P[set] means P[$1]; consider X being set such that A1: x in X iff x in RAT & _P[x] from Separation; X is rational-membered proof let x; assume x in X; then x in RAT by A1; hence thesis by RAT_1:def 2; end; then reconsider X as rational-membered set; take X; let w; w in RAT by RAT_1:def 2; hence thesis by A1; end; scheme IM_Separation {P[set]}: ex X being integer-membered set st for i holds i in X iff P[i] proof defpred _P[set] means P[$1]; consider X being set such that A1: x in X iff x in INT & _P[x] from Separation; X is integer-membered proof let x; assume x in X; then x in INT by A1; hence thesis by INT_1:def 2; end; then reconsider X as integer-membered set; take X; let i; i in INT by INT_1:12; hence thesis by A1; end; scheme NM_Separation {P[set]}: ex X being natural-membered set st for n holds n in X iff P[n] proof defpred _P[set] means P[$1]; consider X being set such that A1: x in X iff x in NAT & _P[x] from Separation; X is natural-membered proof let x; assume x in X; then x in NAT by A1; hence thesis by ORDINAL2:def 21; end; then reconsider X as natural-membered set; take X; let n; n in NAT by ORDINAL2:def 21; hence thesis by A1; end;