Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add new theorems related to restricted class abstraction, mappings, and measurable functions #4537

Merged
merged 12 commits into from
Jan 7, 2025
Merged
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
192 changes: 190 additions & 2 deletions set.mm
Original file line number Diff line number Diff line change
Expand Up @@ -698971,6 +698971,19 @@ not even needed (it can be any class). (Contributed by Glauco
ZUEUIDABCPQUHBDERUMUGBDOZULKUHBDOUJUKUNULBDCEFSTUGABDUAUHBDUBUCUD $.
$}

${
ssrabdf.1 $e |- F/_ x A $.
ssrabdf.2 $e |- F/_ x B $.
ssrabdf.3 $e |- F/ x ph $.
ssrabdf.4 $e |- ( ph -> B C_ A ) $.
ssrabdf.5 $e |- ( ( ph /\ x e. B ) -> ps ) $.
$( Subclass of a restricted class abstraction (deduction form).
(Contributed by Glauco Siliprandi, 5-Jan-2025.) $)
ssrabdf $p |- ( ph -> B C_ { x e. A | ps } ) $=
( wss wral crab ralrimia ssrabf sylanbrc ) AEDKBCELEBCDMKIABCEHJNBCDEGFOP
$.
$}

${
$d A x $. $d B x $.
$( Membership in indexed intersection. See ~ eliincex for a counterexample
Expand Down Expand Up @@ -701137,6 +701150,53 @@ not even needed (it can be any class). (Contributed by Glauco
( mpteq2da ) ABCDEFGH $.
$}

${
dmmpt1.x $e |- F/ x ph $.
dmmpt1.1 $e |- F/_ x B $.
dmmpt1.c $e |- ( ( ph /\ x e. B ) -> C e. V ) $.
$( The domain of the mapping operation, deduction form. (Contributed by
Glauco Siliprandi, 5-Jan-2025.) $)
dmmpt1 $p |- ( ph -> dom ( x e. B |-> C ) = B ) $=
( cmpt eqid dmmptdff ) ABBCDIZCDEFGLJHK $.
$}

${
$d A y $. $d B y $. $d C y $. $d x y $.
fmptff.1 $e |- F/_ x A $.
fmptff.2 $e |- F/_ x B $.
fmptff.3 $e |- F = ( x e. A |-> C ) $.
$( Functionality of the mapping operation. (Contributed by Glauco
Siliprandi, 5-Jan-2025.) $)
fmptff $p |- ( A. x e. A C e. B <-> F : A --> B ) $=
( vy wcel wral cv csb wf nfcv nfv nfcsb1v nfel weq cmpt eleq1d eqtri fmpt
csbeq1a cbvralfw cbvmptf bitri ) DCJZABKAILZDMZCJZIBKBCENUHUKAIBFIBOZUHIP
AUJCAUIDQZGRAISDUJCAUIDUDZUAUEIBCUJEEABDTIBUJTHAIBDUJFULIDOUMUNUFUBUCUG
$.
$}

${
fvmptelcdmf.a $e |- F/_ x A $.
fvmptelcdmf.c $e |- F/_ x C $.
fvmptelcdmf.f $e |- ( ph -> ( x e. A |-> B ) : A --> C ) $.
$( The value of a function at a point of its domain belongs to its
codomain. (Contributed by Glauco Siliprandi, 5-Jan-2025.) $)
fvmptelcdmf $p |- ( ( ph /\ x e. A ) -> B e. C ) $=
( wcel cmpt wf wral eqid fmptff sylibr r19.21bi ) ADEIZBCACEBCDJZKQBCLHBC
EDRFGRMNOP $.
$}

${
fmptdff.1 $e |- F/ x ph $.
fmptdff.2 $e |- F/_ x A $.
fmptdff.3 $e |- F/_ x C $.
fmptdff.4 $e |- ( ( ph /\ x e. A ) -> B e. C ) $.
fmptdff.5 $e |- F = ( x e. A |-> B ) $.
$( A version of ~ fmptd using bound-variable hypothesis instead of a
distinct variable condition for ` ph ` . (Contributed by Glauco
Siliprandi, 5-Jan-2025.) $)
fmptdff $p |- ( ph -> F : A --> C ) $=
( wcel wral wf ralrimia fmptff sylib ) ADELZBCMCEFNARBCGJOBCEDFHIKPQ $.
$}

$(
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Expand Down Expand Up @@ -753519,6 +753579,19 @@ is the step (i) of the proof of Proposition 121E (d) of [Fremlin1]
KUNDUNDJUAUBUCUGABCDULEFGHIJULUHTAUDUEKUIUJ $.
$}

${
smffmptf.x $e |- F/ x ph $.
smffmptf.a $e |- F/_ x A $.
smffmptf.s $e |- ( ph -> S e. SAlg ) $.
smffmptf.b $e |- ( ( ph /\ x e. A ) -> B e. V ) $.
smffmptf.m $e |- ( ph -> ( x e. A |-> B ) e. ( SMblFn ` S ) ) $.
$( A function measurable w.r.t. to a sigma-algebra, is actually a function.
(Contributed by Glauco Siliprandi, 5-Jan-2025.) $)
smffmptf $p |- ( ph -> ( x e. A |-> B ) : A --> RR ) $=
( cr cmpt wf cdm eqid smff dmmpt1 eqcomd feq2d mpbird ) ACLBCDMZNUBOZLUBN
AUCEUBIKUCPQACUCLUBAUCCABCDFGHJRSTUA $.
$}

${
$d A x $.
smffmpt.x $e |- F/ x ph $.
Expand All @@ -753528,8 +753601,7 @@ is the step (i) of the proof of Proposition 121E (d) of [Fremlin1]
$( A function measurable w.r.t. to a sigma-algebra, is actually a function.
(Contributed by Glauco Siliprandi, 23-Oct-2021.) $)
smffmpt $p |- ( ph -> ( x e. A |-> B ) : A --> RR ) $=
( cr cmpt wf cdm eqid smff dmmptdf eqcomd feq2d mpbird ) ACKBCDLZMUANZKUA
MAUBEUAHJUBOPACUBKUAAUBCABUACDFGUAOIQRST $.
( nfcv smffmptf ) ABCDEFGBCKHIJL $.
$}

${
Expand Down Expand Up @@ -754778,6 +754850,122 @@ that every function in the sequence can have a different (partial)
KUEUF $.
$}

${
$d C x $.
smfdmmblpimne.1 $e |- F/ x ph $.
smfdmmblpimne.2 $e |- F/_ x A $.
smfdmmblpimne.3 $e |- ( ph -> S e. SAlg ) $.
smfdmmblpimne.4 $e |- ( ph -> A e. S ) $.
smfdmmblpimne.5 $e |- ( ( ph /\ x e. A ) -> B e. RR ) $.
smfdmmblpimne.6 $e |- ( ph -> ( x e. A |-> B ) e. ( SMblFn ` S ) ) $.
smfdmmblpimne.7 $e |- ( ph -> C e. RR ) $.
smfdmmblpimne.8 $e |- D = { x e. A | B =/= C } $.
$( If a measurable function w.r.t. to a sigma-algebra has domain in the
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If the domain of a measurable function ... is in the sigma-algebra ,...

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hi @wlammen,

Fremlin's book (which I'm following) states:

"I seek to deal with functions which are not defined on the whole of the space X under consideration. I believe that there are compelling reasons for facing up to such functions at an early stage."

This perspective is crucial, especially when addressing the limits of functions, which can have "bizarre" domains—even when the initial functions are defined on the entire sigma-algebra. For more details, see ~smflim.

Additionally, ~smfmbfcex provides examples of measurable functions with non-measurable domains (e.g., take
X to be the Vitali set). My definition includes a broader class of measurable functions compared to MblFn.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I did not expect this. So OK then.

sigma-algebra, the set of elements that are not mapped to a given real,
is in the sigma-algebra (Contributed by Glauco Siliprandi,
5-Jan-2025.) $)
smfdmmblpimne $p |- ( ph -> D e. S ) $=
( clt wbr crab wcel rexrd cun wne cv wa cxr adantr pimxrneun eqtrid crest
co salrestss cr smfpimltxrmptf sseldd smfpimgtxrmptf saluncld eqeltrd ) A
FDEPQBCRZEDPQBCRZUAZGAFDEUBBCRUTOABCDEHABUCCSZUDDLTAEUESVAAENTZUFUGUHAGUR
USJAGCUIUJZGURAGCJKUKZABCDEGULHIJLMVBUMUNAVCGUSVDABCDGEULHIJLMVBUOUNUPUQ
$.
$}

${
$d A y $. $d B y $. $d C y $. $d D y $. $d V x $. $d ph y $.
$d x y $.
smfdivdmmbl.1 $e |- F/ x ph $.
smfdivdmmbl.2 $e |- F/_ x B $.
smfdivdmmbl.3 $e |- ( ph -> S e. SAlg ) $.
smfdivdmmbl.4 $e |- ( ph -> A e. S ) $.
smfdivdmmbl.5 $e |- ( ph -> B e. S ) $.
smfdivdmmbl.6 $e |- ( ( ph /\ x e. B ) -> D e. W ) $.
smfdivdmmbl.7 $e |- ( ph -> ( x e. B |-> D ) e. ( SMblFn ` S ) ) $.
smfdivdmmbl.8 $e |- E = { x e. B | D =/= 0 } $.
$( If a functions and a sigma-measurable function have domains in the
sigma-algebra, the domain of the division of the two functions is in the
sigma-algebra. This is the third statement of Proposition 121H of
[Fremlin1] p. 39 . Note: While the theorem in the book assumes both
functions are sigma-measurable, this assumption is unnecessary for the
part concerning their division, for the function at the numerator (it is
needed only for the function at the denominator). (Contributed by
Glauco Siliprandi, 5-Jan-2025.) $)
smfdivdmmbl $p |- ( ph -> ( A i^i E ) e. S ) $=
( cc0 cr nfcv smffmptf fvmptelcdmf 0red smfdmmblpimne salincld ) AFCGKLAB
DEQGFIJKMABDERJBRSABDEFHIJKNOTUAOAUBPUCUD $.
$}

${
$d A x $.
smfpimne.p $e |- F/ x ph $.
smfpimne.x $e |- F/_ x F $.
smfpimne.s $e |- ( ph -> S e. SAlg ) $.
smfpimne.f $e |- ( ph -> F e. ( SMblFn ` S ) ) $.
smfpimne.d $e |- D = dom F $.
smfpimne.a $e |- ( ph -> A e. RR* ) $.
$( Given a function measurable w.r.t. to a sigma-algebra, the preimage of
reals that are different from a value in the extended reals is in the
subspace of sigma-algebra induced by its domain. (Contributed by Glauco
Siliprandi, 5-Jan-2025.) $)
smfpimne $p |- ( ph -> { x e. D | ( F ` x ) =/= A } e. ( S |`t D ) ) $=
( cv cfv wne crab clt wbr cun wcel crest co wa cr ffvelcdmda rexrd adantr
smff cxr pimxrneun smfdmss subsaluni eqid subsalsal smfpimltxr smfpimgtxr
saluncld eqeltrd ) ABMZFNZCOBDPUTCQRBDPZCUTQRBDPZSEDUAUBZABDUTCGAUSDTZUCU
TADUDUSFADEFIJKUHUEUFACUITVDLUGUJAVCVAVBADEVCVCIADEIADEFIJKUKULVCUMUNABCD
EFHIJKLUOABCDEFHIJKLUPUQUR $.
$}

${
$d A x $.
smfpimne2.p $e |- F/ x ph $.
smfpimne2.x $e |- F/_ x F $.
smfpimne2.s $e |- ( ph -> S e. SAlg ) $.
smfpimne2.f $e |- ( ph -> F e. ( SMblFn ` S ) ) $.
smfpimne2.d $e |- D = dom F $.
$( Given a function measurable w.r.t. to a sigma-algebra, the preimage of
reals that are different from a value is in the subspace sigma-algebra
induced by its domain. Notice that ` A ` is not assumed to be an
extended real. (Contributed by Glauco Siliprandi, 5-Jan-2025.) $)
smfpimne2 $p |- ( ph -> { x e. D | ( F ` x ) =/= A } e. ( S |`t D ) ) $=
( cxr wcel cfv wa nfv nfan adantr simpr wn cv crab crest co csalg csmblfn
wne smfpimne wss cdm nfdm nfcxfr ssrab2f a1i ssidd wceq nne cr ffvelcdmda
smff rexrd eqeltrrd sylan2b adantllr simpllr condan ssrabdf eqssd smfdmss
subsaluni eqeltrd pm2.61dan ) ACLMZBUAZFNZCUGZBDUBZEDUCUDZMAVMOBCDEFAVMBG
VMBPQHAEUEMVMIRAFEUFNMVMJRKAVMSUHAVMTZOZVQDVRVTVQDVQDUIVTVPBDBDFUJKBFHUKU
LZUMUNVTVPBDDWAWAAVSBGVSBPQVTDUOVTVNDMZOVPVMAWBVPTZVMVSWCAWBOZVOCUPZVMVOC
UQWDWEOVOCLWDWESWDVOLMWEWDVOADURVNFADEFIJKUTUSVARVBVCVDAVSWBWCVEVFVGVHADV
RMVSADEIADEFIJKVIVJRVKVL $.
$}

${
smfdivdmmbl2.1 $e |- F/ x ph $.
smfdivdmmbl2.2 $e |- F/_ x F $.
smfdivdmmbl2.3 $e |- F/_ x G $.
smfdivdmmbl2.4 $e |- ( ph -> S e. SAlg ) $.
smfdivdmmbl2.5 $e |- ( ph -> F : A --> V ) $.
smfdivdmmbl2.6 $e |- ( ph -> G e. ( SMblFn ` S ) ) $.
smfdivdmmbl2.7 $e |- ( ph -> A e. S ) $.
smfdivdmmbl2.8 $e |- ( ph -> dom G e. S ) $.
smfdivdmmbl2.9 $e |- D = { x e. dom G | ( G ` x ) =/= 0 } $.
smfdivdmmbl2.10 $e |- H = ( x e. ( dom F i^i D ) |-> ( ( F ` x ) / ( G ` x
) ) ) $.
$( If a functions and a sigma-measurable function have domains in the
sigma-algebra, the domain of the division of the two functions is in the
sigma-algebra. This is the third statement of Proposition 121H of
[Fremlin1] p. 39 . Note: While the theorem in the book assumes both
functions are sigma-measurable, this assumption is unnecessary for the
part concerning their division, for the function at the numerator. It
is required only for the function at the denominator. (Contributed by
Glauco Siliprandi, 5-Jan-2025.) $)
smfdivdmmbl2 $p |- ( ph -> dom H e. S ) $=
( cdm cin cfv cdiv nfdm cc0 wne crab nfrab1 nfcxfr nfin ovex dmmptif fdmd
cv co eqeltrd crest salrestss eqid smfpimne2 eqeltrid sseldd salincld ) A
HTFTZDUAZEBVEBUNZFUBZVFGUBZUCUOHBVDDBFKUDBDVHUEUFZBGTZUGZRVIBVJUHUIUJVGVH
UCUKSULAEVDDMAVDCEACIFNUMPUPAEVJUQUOZEDAEVJMQURADVKVLRABUEVJEGJLMOVJUSUTV
AVBVCVA $.
$}

$( (End of Glauco Siliprandi's mathbox.) $)
$( End $[ set-mbox-gs.mm $] $)

Expand Down
Loading