!"#$ %& !"!#$!" !" #$%$& '&()*(+ !" " #$%&'()'($ ! "#$ %&'() *&+&(&,-. )/01 *2.2/32$! 4! 51$2. 6-$ *&+&(&,-. )/012' *2.2/ &(70%2 -8-' 9#$#.(- :# 1#*#$(- .&;)( %&'() &(70%232$! <! 51'2 6-$ .=7# =/#$-'3# S ⊂ T .&;)()') %0>(010' -.- *&+&(&,- :#$-(%-'! ?>#$ (X, T ) *2.2/ -%# (X, S ) 3# *2.2/32$! !"#$% (X, S ) )/012'2' @#$ 082. A$*=%= 01'2 /070'30 (X, T ) )/012'2' 30 6-$ A$*=%=3=$! B2.2/ &(3)>) -8-'C 6) A$*='='C (X, T ) )/012'30 %&'() 6-$ 0(* A$*=%= :0$32$! D) 0(* A$*=C (X, S ) '-' 3# %&'() 6-$ A$*=%=3=$! D)')' .0$;2*2 9#'#( &(0$0. 9#8#$%-/3-$! E$'#>-'C [0, 1] 0$0(2>2 =/#$-'3#.%0(* *&+&(&,-1# S C 01$2. *&+&(&,-1# -%# A 3-1#(-7! S ⊂ A 32$! ([0, 1], S '-' *2.2/ &(3)>)') 6-(-1&$)/! 570 ([0, 1], A ) *2.2/ 3#>-(3-$! F! (X, S ) :# (X, T ) )/01(0$2 *2.2/ -%# 10 S = T 3-$ 10 30 7).01#%# #3-(#G 7#/(#$H 10'- 6-$-%- A*#.-'3#' -'I# 10 30 .060 3#>-(3-$! !"#"$ %$&'"( )&%*+ ,-../ -0,%1%(% #&2%0 3,4'-.%$56 !"#$% S ⊂ T &(3)>)') :0$%010(27! I : (X, T ) → (X, S ) A/3#;(-. 3A'=;=7= 66A :# %=$#.(-3-$! J @0(3# 6-$ *&+&(&,-. #;10+2 3A'=;=7=3=$! K&(012%1(0C T = S &(0I0.*2$! L! X %012(070/ %&'%)/ 6-$ .=7# &(%)' D) .=7# =/#$-'3# C = {T : 10 T ′ %&'()3)$ 10 30 T = X} M L! N 0-(#%- 6-$ *&+&(&,-3-$! D)'0 O012(06-(-$ B=7(#1#'(#$ B&+&(&,-%- 3#'-(-$! D-$ 0(*G.=7#'-' 6) *&+&(&,-1# 9A$# *2.2/ &(70%2 -8-' %&'() &(70%2 9#$#.(- :# 1#*#$(-3-$! FP !"#$ %&' ()*)+")* !" !"#$% #$%&' (&)*+,-.&./0% )1+12 $&(3(41 (51+)1/6 7(/81) $&(/(+9 :$%&' $&-(;(% <0/ +,-.%0% )1+12 $&(-(;(3(41%1 =>:)./.&0-6 ?./ @(%=0 <0/ A = {a1 , a2 , . . . , an , . . .} :(;1&(<0&0/ :$%:'2 +,-.:0%0 A,8,%.&0-6 ?./ n = 1, 2, . . . , n, . . .) 050% An = A′ ∪{a1 , a2 , . . . , an } +,-.:0 (51+)1/B 5,%+, A′ ∈ C C. {a1 , a2 , . . . , an } ∈ C A0/6 Sn 7$&(;3( =>/,&.3.40 =0<0 A ⊂ n=1 An A0/B ;(%0 {An : n ∈ N}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⊂ T $&A'4'%' C(/:(;(&1-6 D' C(/:(;1- (&)1%A( H ′ ⊂ T ′ $&(3(+)1/B ;(%0 H )$H$&$I0:0%A. +(H(&1 $&(% @./ +,-. T )$H$&$I0:0%A. A. +(H(&1 $&-(&1A1/6 7(/81) $&(/(+ T )$H$&$I0:0%A. )1+12 $&(% @./ +,-. H )$H$&$I0:0%A. A. )1+12 $&(3(+)1/6 O;/13(9 G.$/.- !6 6P ';(/1%3(9 )1+12 <0/ '2(;A( <0/ (&) +,-.%0% )1+12 $&-(:1 050% +(H(&1 $&-(:1 =./.+&0 C. ;.)./&0A0/6 D,),% <'%&(/1 <0/ (/(;( =.)0/0/:.+ 8>;&. A0;.<0&0/02Q A ∈ T ′ ⇒ A +,-.:0 T )$H$&$I0:0%. =>/. )1+12A1/ ⇒ A +,-.:0 H )$H$&$I0:0%. =>/. )1+12A1/ ⇒ A +,-.:0 H )$H$&$I0:0%. =>/. +(H(&1A1/ ⇒A∈H′ E @(&A. T ′ ⊂ H ′ A,/B ;(%0 T )$H$&$I0:0%A. +(H(&1 $&(% @./ +,-. H )$H$&$I0:0%A. A. +(H(&1A1/6 R;&.;:. H = T $&-(&1A1/6 S6 Q ∩ (R − Q) = ∅ A0/9 (-( Q ∩ (R − Q) = R A0/6 T6 Q '2(;1 C. Q = (R − Q) '2(;1 (;/1&(<0&0/ 0+0 '2(;A1/6 F$&(;1:1;&( U+0%30 #(;1&(<0&-. O+:0;$-'%' :(4&(/&(/6 ′ V6 [0, 1] ∩ Q )(-(-.% :1%1/&1A1/9 (-( )1+12 A.40&A0/6 !" "# $%&'()*()% 6 W./5.& .+:.%0% (51+ ;( A( ;(/1*(51+ @05<0/ (/(&141%1% )1+12 $&-(A141%1 =>:* )./0%026 !"#$% !" " #$%$& '&()*(+ ! "#$ {(−n, +n) : n ∈ N} #%&'(% R )'*+'& (#,-&#* ./0'(%1%1 #+-. 2%* 3*4/(/5 6/*7 80# 29 3*4/6'1 (:1&9 2%* #&4 3*4/ ('+%&'0';7 <,&',('= R )'*+'& (#,-&#* ./0'(% 4-.-; 6'>%&6%*7 "2$ {( n1 , 1) : n ∈ N} #%&'(% (0, 1) #*#&->-1-1 #+-. 2%* 3*4/(/6/*7 80# 29 3*4/6'1 (:1&9 2%* #&4 3*4/ ('+%&'0';7 <,&',('= (0, 1) #+-. #*#&->- 4-.-; 6'>%&6%*7 ?7 (X, T ) 4-.-; 9;#,-16#= 4-.-; %.% #&45./0'1%1 2%&'@%0%1%1 A' #*#.'(%4%1%1 4-.-; :&69>919 )3(4'*%1%;7 !"#$% (X, T ) 9;#,-1- 4-.-; .#29& '40'.&' :191 B#9(6:*C :&69>919 .#29& '6%,:*9;7 D':*'0 !7 7E 9,#*-1F#= 4-.-; 9;#,-1 4-.-; #&4 ./0'&'*% .#G#&-6-*7 A, B ⊂ X #&4 ./0'&'*% 4-.-; %(' .#G#&-6-*&#*7 H I#&6' A ∪ B 2%&'@%0% A' A ∩ B #*#.'(%4% .#G#&- ./0'&'*6%*7 A ∪ B 2%&'@%0%1%1 2%* #+-. 3*4/(/ U :&(917 X − A ∪ B #+-. :&69>916#1 U ∪ (X − A ∪ B) #%&'(% X 9;#,-1-1 #+-. 2%* 3*4/(/6/*7 H I#&6' (:1&9 2%* #&4 3*4/(/ ('+%&'2%&%*7 J9 (:1&9 3*4/6'1 X − A ∩ B ./0'(%1% #4#*(#.= )'*% .#&#1 #%&' A ∩ B #*#.'(%4%1%1 (:1&9 2%* 3*4/(/ :&#F#.4-*7 A ∩ B #*#.'(%4%1%1 4-.-;&->-1- )3(4'*0'. %+%1 6' 2'1;'* 6/@/1F',% 9,)95 &#,#2%&%*%;7 A ∩ B #*#.'(%4%1%1 2%* #+-. 3*4/(/ V :&(917 X − A ∩ B #+-. :&69>916#1 V ∪ (X − A ∩ B) #%&'(% X 9;#,-1-1 #+-. 2%* 3*4/(/6/*7 H I#&6' (:1&9 2%* #&4 3*4/(/ ('+%&'2%&%*7 J9 (:1&9 3*4/6'1 X − A ∩ B ./0'(%1% #4#*(#.= )'*% .#&#1 #%&' A ∩ B #*#.'(%4%1%1 (:1&9 2%* 3*4/(/ :&#F#.4-*7 &'()*% J9 .%4#G4# 4-.-;-0(- "K9#(%F:0G#F4$ B#9(6:*C 9;#,&#*-1# 4-.-; "F:0G#F4$ 9;#, 6%,:*9;7 J#;- .#,1#.&#*= B#9(6:*C :&0# .:@9&919 .:,0#;7 H 69*906#= ,9.#*-6#.% %(G#4 )'+'*(%; :&9*L +/1./ 4-.-; #&45./0'&'*%1 .#G#&:&0#(- #1F#. B#9(6:*C 9;#,&#*-16# )'+'*&%6%*7 E7 M:1(9; 2%* ./0'= .'16% /;'*%16'.% ,-./0 #12/343./35 #-6-/-7898.3 )3*' 4-.-;6-*7 N'6'1O !"#$% (X, S ) (:1&9 4/0&','1&'* "F:P1%4'$ 4:G:&:Q%(% :&(917 O = {Uı : Uı ∈ S , ı ∈ I} 2%* #+-. 3*4/ :&(917 J9 3*4/6'1 *#()'&' 2%* U0 ∈ O #+-. ′ ./0'(%1% ('+'&%07 J9191 4/0&','1% (:1&969*L ,#1% U0 = {x1 , x2 , . . . , xn } ′ #%4 I'* xi 1:.4#(-1- %+'*'1 2%* Ui ∈ O ('+%&'2%&%*7 :&9*7 U0 4/0&','1%1' Sn J3,&'F'= X = i=0 Ui :&#F#.4-*7 R7 8,*-. 4:G:&:Q%,' )3*' 2%* ./0'1%1 4-.-; :&0#(- %+%1 )'*'.&% A' ,'4'*&% .:@9& (:1&9 :&0#(-6-*7 N'6'1O !"#$% (X, A ) #,*-. 9;#, S :&(917 B'* x ∈ X %+%1 4'. 3>'&% {x} ./0'(% #+-.4-*7 H I#&6'= X = {{x} : x ∈ X} :&69>916#1 O = {{x} : x ∈ X}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{a1 , a2 , . . . , an , . . .} -%&',%1+,+* -5.-#$ ;34)-+.+ 83@3.)= ,+4/ D)* n = 1, 2, . . . , n, . . .) +:+. An = A′ ∪ {a1 , a2 , . . . , an } ;34)-+ %:';<'*F :3.;3 A′ ∈ C () {a1 , a2 , . . . , an } ∈ C 8+*/ Sn ?5,%&>% BC*3,)>)9+ B+1+ A ⊂ n=1 An 8+*F &%.+ {An : n ∈ N} %+,)-+ A .'. %:'; 1+* C*<3-383*/ G# C*<38). -5.,# 1+* %,<=C*<3 -):+,)4)$/ H E%,8) A <';'$ 8)9+,8+*/ I)4); ;+ -%&',%1+,* -5.-#$ ;34),)*A 0%&',%1+,+* 234,)&).,)* 2565,57+-+.) BC*) <';'$ 5,%4%$,%*/ D)* -5.-#$ ;34)8). -%&',%1+,+* 1+* %,< ;34) -):+,)1+,)>)9+.) BC*)A -5.-#$ ;34),)* 8) 0%&',%1+,+* 234,)&).,)* 2565,57+-+.) BC*) <';'$ 5,%4%$,%*/ J/ 2';'$ 1+* #$%&8%. 1+* D%#-85*K #$%&' 3$)*+.) <%.'4,' 1+*)=1+* -3*);,+ 1+* L5.;-+&5.#. 1+* <565,57+; )@&%6' 8C.3@343 5,%>%9'.' BC-<)*+.+$/ !"#$% (X, T <';'$ #$%&A (Y, H ) D%#-85*L #$%&' () f : X → Y L5.;-+= &5.# -3*);,+ () 11C 5,-#./ f −1 (H ) = {f −1 (H) : H ∈ H } %+,)-+ X 3$)*+.8) 1+* <565,57+8+* M1;$/ 2)*- *)-+4 <565,57+-+A +$83@), <5= 65,57+A 6*57)><+() <565,57+N/ O$83@), <565,57+A f &+ -3*);,+ ;',%. ). ;%1% <565,57+ 5,8#9#.8%. f −1 (H ) ⊂ T 8+*/ P<) &%.8%.A X ;34)-+ 3$)*+.8);+ 1+* D%#-85*K <565,57+-+ 1+* <';'$ <565,57+8). ;%1% 5,%4%$ M1;$ !/ / M N Q*51,)4N/ H E%,8) f −1 (H ) = T 8+*/ G# +-) f −1 : Y → X <)*- L5.;-+&5.#.#. 8% -3*);,+ 5,4%-' 8)4);<+*/ P&,)&-)A P.)*4) "/ / #&%*'>% f 1+* )@&%6' 8C.3@34383*/ !"# $%&%' ()*)+ ,+-$'-& !". *-&/- 0&12'%/'%& / (X, T ) <';'$ () (Y, H ) D%#-85*K +-) -3*);,+ f :→ Y L5.;-+&5.# ;%6%,'8'*/ RC-<)*+.+$/ !"#$% A ∈ T ′ +-) A ;34)-+ T ′ &) BC*) <';'$8'*/ H E%,8) -3*);,+ L5.;= -+&5. %,<'.8%;+ *)-4+ f (A) ⊂ Y <';'$8'*/ (Y, H ) D%#-85*K 5,8#9#.8%. f (A) ⊂ Y ;%6%,'8'*/ "/ Y <';'$ +-) π1 : X × Y → X +$83@343 ;%6%,' 1+* 8C.3@3483*/ RC-<)*+.+$/ !"#$% (Y, Y ) <';'$ 1+* #$%& 5,-#./ S%*6'4 <565,57+-+.+ (X × Y, P) +,) BC-<)*),+4/ A ⊂ X × Y ;%6%,' +-) X − π1 (A) .'. X +:+.8) %:'; 5,8#9#.# !"#" $%&'% (&)*+,'+,& !" /A #$%&'()'*+,+-. /+( x ∈ X − π1 (A) $0'%+1+ 23431'*+). 5'( y +6+1 (x, y) ∈ 27(. A 89:9*7 ;*2<0<1291 X × Y − A 9678&7(. =,*',%' >'( y +6+1 $,*' ?+( Uxy ∈ B(x) @' Vy ∈ B(y) 8;)4<*<8*9(7 @9(27( 8+ (x, y) ∈ Uxy × Vy ⊂ X × Y − A ;*9A98&7(. /< 2<(<)29 {Vy : y ∈ Y } 9+*'%+ Y 1+1 ?+( 9678 $(&3%3 ;*<(. Y &787- ;*2<0<1291 ?<1<1 %;1*< ?+( 9*& $(&3%3 @9(27(. /< %;1*< $(&3,' {Vyi : i = 1, 2, . . . , n} 2+,'*+). B+)2+ U = Uxy1 ∩ Uxy2 ∩ . . . ∩ Uxyn 83)'%+1+ &917)*9,9*7). U ∈ B(x) @' U × Y ⊂ X × Y − A ;*9A98&7(. U ∩ π1 (A) = ∅ 2+(. 5'( x ∈ X − π1 (A) +6+1 ?< ,9:7*9?+*'A'0+1' #$(' X − π1 (A) 171 X +6+12' 9678 ;*2<0< ;(&9,9 6789(. C9(:7) &;:;*;D+%+ +-2343) E;18%+,;1*9(717 %3('8*+ 87*91 '1 89?9 2;8<*< &;:;*;D+2+( F?8-. =(1'8 G. . H. C9(:7) &;:;*;D+%+1+ X ×Y, P +*' #$%&'('*+). I<89(7298+ 2343134*'J pi−1 2 (Y ) ⊂ P ?9071&7%7171 @9(*70717 %$,*','?+*+(+-. −1 K9?++ pi−1 2 (Y ) &;:;*;D+%+ &787-27(. K ⊂ Y 83)'%+ &787- +%' pi2 (K) 83L −1 )'%+ pi2 (Y ) &;:;*;D+%+1' #$(' &787- ;*9A98&7(. M >9*2' 9,17 &;:;*;D+,' #$(' 89:9*727(. =,*',%' P &;:;*;D+%+1' #$( 2' 89:9*7 ;*<(. =&' ,91291 π2 opi−1 2 (K) = K 27(. ". Y &787- @' >9<%2;(N +%' f : X → Y 2$1343)3131 %3('8*+ ;*)9%7 +6+1 #'('8*+ @' ,'&'(*+ 8;4<* Gf = {(x, f (x)) : x ∈ X} #(9O0+1+1 X × Y +6+12' 89:9*7 ;*)9%727(. !"#$% / G +%' y 6= f (x) !"!#$%&%' G′ 131 9678 ;*2<0<1< #$%&'()'*+,+-. (x, y) ∈ 2+(. Y 59<%2;(N ;*2<0<1291 y +*' f (x) 1;8&9*9(7171 8'%+4)','1 ?+('( 8;)L 4<*<0< @9(27(. /<1*9(7 y ∈∈ B(y) @' f (x) ∈ W ∈ B(f (x)) +*' #$%&'('*+). f %3('8*+ ;*2<0<1291 f (U ) ⊂ W ⊂ (Y −V ) ;*9A98 ?+6+)2' ?+( x ∈ U ∈ B(x) 8;)4<*<0< @9(27(. /<(9291 (x, y) ∈ U × V ∩ G = ∅ ;*2<0< #$(3*3(. 5'( (x, y) ∈ / G +6+1 ?< $-'*+8 @9( ;*2<0<19 #$(' G′ 9678&7(. (!#!)$%&%' G ⊂ X × Y #(9O0+ 89:9*7 ;*%<1. 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