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$( This is the Metamath database hol.mm. $)
$( Metamath is a formal language and associated computer program for
archiving, verifying, and studying mathematical proofs, created by Norman
Dwight Megill (1950--2021). For more information, visit
https://us.metamath.org and
https://github.com/metamath/set.mm, and feel free to ask questions at
https://groups.google.com/g/metamath. $)
$( The database hol.mm was created by Mario Carneiro on 7-Oct-2014. $)
$( !
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#
Metamath source file for higher-order logic
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#
~~ PUBLIC DOMAIN ~~
This work is waived of all rights, including copyright, according to the CC0
Public Domain Dedication. https://creativecommons.org/publicdomain/zero/1.0/
Mario Carneiro - email: di.gama at gmail.com
$)
$(
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#
Foundations
#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#
$)
$( Declare the primitive constant symbols for lambda calculus. $)
$c var $. $( Typecode for variables (syntax) $)
$c type $. $( Typecode for types (syntax) $)
$c term $. $( Typecode for terms (syntax) $)
$c |- $. $( Typecode for theorems (logical) $)
$c : $. $( Typehood indicator $)
$c . $. $( Separator $)
$c |= $. $( Context separator $)
$c bool $. $( Boolean type $)
$c ind $. $( 'Individual' type $)
$c -> $. $( Function type $)
$c ( $. $( Open parenthesis $)
$c ) $. $( Close parenthesis $)
$c , $. $( Context comma $)
$c \ $. $( Lambda expression $)
$c = $. $( Equality term $)
$c T. $. $( Truth term $)
$c [ $. $( Infix operator $)
$c ] $. $( Infix operator $)
$v al $. $( Greek alpha $)
$v be $. $( Greek beta $)
$v ga $. $( Greek gamma $)
$v de $. $( Greek delta $)
$v x y z f g p q $. $( Bound variables $)
$v A B C F R S T $. $( Term variables $)
$( $j syntax 'var' 'type' 'term'; bound 'var'; $)
$( Let variable ` al ` be a type. $)
hal $f type al $.
$( Let variable ` be ` be a type. $)
hbe $f type be $.
$( Let variable ` ga ` be a type. $)
hga $f type ga $.
$( Let variable ` de ` be a type. $)
hde $f type de $.
$( Let variable ` x ` be a var. $)
vx $f var x $.
$( Let variable ` y ` be a var. $)
vy $f var y $.
$( Let variable ` z ` be a var. $)
vz $f var z $.
$( Let variable ` f ` be a var. $)
vf $f var f $.
$( Let variable ` g ` be a var. $)
vg $f var g $.
$( Let variable ` p ` be a var. $)
vp $f var p $.
$( Let variable ` q ` be a var. $)
vq $f var q $.
$( Let variable ` A ` be a term. $)
ta $f term A $.
$( Let variable ` B ` be a term. $)
tb $f term B $.
$( Let variable ` C ` be a term. $)
tc $f term C $.
$( Let variable ` F ` be a term. $)
tf $f term F $.
$( Let variable ` R ` be a term. $)
tr $f term R $.
$( Let variable ` S ` be a term. $)
ts $f term S $.
$( Let variable ` T ` be a term. $)
tt $f term T $.
$( A var is a term. $)
tv $a term x : al $.
$( The type of all functions from type ` al ` to type ` be ` . $)
ht $a type ( al -> be ) $.
$( The type of booleans (true and false). $)
hb $a type bool $.
$( The type of individuals. $)
hi $a type ind $.
$( A combination (function application). $)
kc $a term ( F T ) $.
$( A lambda abstraction. $)
kl $a term \ x : al . T $.
$( The equality term. $)
ke $a term = $.
$( Truth term. $)
kt $a term T. $.
$( Infix operator. $)
kbr $a term [ A F B ] $.
$( Context operator. $)
kct $a term ( A , B ) $.
$c wff $. $( Not used; for mmj2 compatibility $)
$( $j syntax 'wff'; syntax '|-' as 'wff'; $)
$( Internal axiom for mmj2 use. $)
wffMMJ2 $a wff A |= B $.
$( Internal axiom for mmj2 use. $)
wffMMJ2t $a wff A : al $.
${
idi.1 $e |- R |= A $.
$( The identity inference. (Contributed by Mario Carneiro, 9-Oct-2014.) $)
idi $p |- R |= A $=
( ) C $.
$}
${
idt.1 $e |- A : al $.
$( The identity inference. (Contributed by Mario Carneiro, 9-Oct-2014.) $)
idt $p |- A : al $=
( ) C $.
$}
${
ax-syl.1 $e |- R |= S $.
ax-syl.2 $e |- S |= T $.
$( Syllogism inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-syl $a |- R |= T $.
$( Syllogism inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
syl $p |- R |= T $=
( ax-syl ) ABCDEF $.
$}
${
ax-jca.1 $e |- R |= S $.
ax-jca.2 $e |- R |= T $.
$( Join common antecedents. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-jca $a |- R |= ( S , T ) $.
$( Syllogism inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
jca $p |- R |= ( S , T ) $=
( ax-jca ) ABCDEF $.
$}
${
syl2anc.1 $e |- R |= S $.
syl2anc.2 $e |- R |= T $.
syl2anc.3 $e |- ( S , T ) |= A $.
$( Syllogism inference. (Contributed by Mario Carneiro, 7-Oct-2014.) $)
syl2anc $p |- R |= A $=
( kct jca syl ) BCDHABCDEFIGJ $.
$}
${
ax-simpl.1 $e |- R : bool $.
ax-simpl.2 $e |- S : bool $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-simpl $a |- ( R , S ) |= R $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-simpr $a |- ( R , S ) |= S $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
simpl $p |- ( R , S ) |= R $=
( ax-simpl ) ABCDE $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
simpr $p |- ( R , S ) |= S $=
( ax-simpr ) ABCDE $.
$}
${
ax-id.1 $e |- R : bool $.
$( The identity inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-id $a |- R |= R $.
$( The identity inference. (Contributed by Mario Carneiro, 7-Oct-2014.) $)
id $p |- R |= R $=
( ax-id ) ABC $.
$}
${
ax-trud.1 $e |- R : bool $.
$( Deduction form of ~ tru . (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-trud $a |- R |= T. $.
$( Deduction form of ~ tru . (Contributed by Mario Carneiro,
7-Oct-2014.) $)
trud $p |- R |= T. $=
( ax-trud ) ABC $.
ax-a1i.2 $e |- T. |= A $.
$( Change an empty context into any context. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
a1i $p |- R |= A $=
( kt ax-trud syl ) BEABCFDG $.
$}
${
ax-cb.1 $e |- R |= A $.
$( A context has type boolean.
This and the next few axioms are not strictly necessary, and are
conservative on any theorem for which every variable has a specified
type, but by adding this axiom we can save some typehood hypotheses in
many theorems. The easy way to see that this axiom is conservative is
to note that every axiom and inference rule that constructs a theorem of
the form ` R |= A ` where ` R ` and ` A ` are type variables, also
ensures that ` R : bool ` and ` A : bool ` . Thus it is impossible to
prove any theorem ` |- R |= A ` unless both ` |- R : bool ` and
` |- A : bool ` had been previously derived, so it is conservative to
deduce ` |- R : bool ` from ` |- R |= A ` . The same remark applies to
the construction of the theorem ` ( A , B ) : bool ` - there is only one
rule that creates a formula of this type, namely ~ wct , and it requires
that ` A : bool ` and ` B : bool ` be previously established, so it is
safe to reverse the process in ~ wctl and ~ wctr . (Contributed by
Mario Carneiro, 8-Oct-2014.) $)
ax-cb1 $a |- R : bool $.
$( A theorem has type boolean. (This axiom is unnecessary; see ~ ax-cb1 .)
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-cb2 $a |- A : bool $.
$}
${
wctl.1 $e |- ( S , T ) : bool $.
$( Reverse closure for the type of a context. (This axiom is unnecessary;
see ~ ax-cb1 .) Prefer ~ wctl . (New usage is discouraged.)
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-wctl $a |- S : bool $.
$( Reverse closure for the type of a context. (This axiom is unnecessary;
see ~ ax-cb1 .) Prefer ~ wctr . (New usage is discouraged.)
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-wctr $a |- T : bool $.
$( Reverse closure for the type of a context. (This axiom is unnecessary;
see ~ ax-cb1 .) (Contributed by Mario Carneiro, 8-Oct-2014.) $)
wctl $p |- S : bool $=
( ax-wctl ) ABCD $.
$( Reverse closure for the type of a context. (This axiom is unnecessary;
see ~ ax-cb1 .) (Contributed by Mario Carneiro, 8-Oct-2014.) $)
wctr $p |- T : bool $=
( ax-wctr ) ABCD $.
$}
${
mpdan.1 $e |- R |= S $.
mpdan.2 $e |- ( R , S ) |= T $.
$( Modus ponens deduction. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
mpdan $p |- R |= T $=
( ax-cb1 id syl2anc ) CAABABADFGDEH $.
$}
${
syldan.1 $e |- ( R , S ) |= T $.
syldan.2 $e |- ( R , T ) |= A $.
$( Syllogism inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
syldan $p |- ( R , S ) |= A $=
( kct ax-cb1 wctl wctr simpl syl2anc ) ABCGZBDBCBCDMEHZIBCNJKEFL $.
$}
${
simpld.1 $e |- R |= ( S , T ) $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
simpld $p |- R |= S $=
( kct ax-cb2 wctl wctr simpl syl ) ABCEZBDBCBCKADFZGBCLHIJ $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
simprd $p |- R |= T $=
( kct ax-cb2 wctl wctr simpr syl ) ABCEZCDBCBCKADFZGBCLHIJ $.
$}
${
trul.1 $e |- ( T. , R ) |= S $.
$( Deduction form of ~ tru . (Contributed by Mario Carneiro,
7-Oct-2014.) $)
trul $p |- R |= S $=
( kt kct ax-cb1 wctr trud id syl2anc ) BADAADABDAECFGZHAKICJ $.
$}
$( The equality function has type ` al -> al -> bool ` , i.e. it is
polymorphic over all types, but the left and right type must agree.
(New usage is discouraged.) (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-weq $a |- = : ( al -> ( al -> bool ) ) $.
$( The equality function has type ` al -> al -> bool ` , i.e. it is
polymorphic over all types, but the left and right type must agree.
(Contributed by Mario Carneiro, 7-Oct-2014.) $)
weq $p |- = : ( al -> ( al -> bool ) ) $=
( ax-weq ) AB $.
${
ax-refl.1 $e |- A : al $.
$( Reflexivity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-refl $a |- T. |= ( ( = A ) A ) $.
$}
$( Truth type. (Contributed by Mario Carneiro, 10-Oct-2014.) $)
wtru $p |- T. : bool $=
( ke kc kt hb ht weq ax-refl ax-cb1 ) AABABCDDDEEADFGH $.
$( Tautology is provable. (Contributed by Mario Carneiro, 7-Oct-2014.) $)
tru $p |- T. |= T. $=
( kt wtru id ) ABC $.
${
ax-eqmp.1 $e |- R |= A $.
ax-eqmp.2 $e |- R |= ( ( = A ) B ) $.
$( Modus ponens for equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-eqmp $a |- R |= B $.
$}
${
ax-ded.1 $e |- ( R , S ) |= T $.
ax-ded.2 $e |- ( R , T ) |= S $.
$( Deduction theorem for equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-ded $a |- R |= ( ( = S ) T ) $.
$}
${
wct.1 $e |- S : bool $.
wct.2 $e |- T : bool $.
$( The type of a context. (Contributed by Mario Carneiro, 7-Oct-2014.)
(New usage is discouraged.) $)
ax-wct $a |- ( S , T ) : bool $.
$( The type of a context. (Contributed by Mario Carneiro, 7-Oct-2014.) $)
wct $p |- ( S , T ) : bool $=
( ax-wct ) ABCDE $.
$}
${
wc.1 $e |- F : ( al -> be ) $.
wc.2 $e |- T : al $.
$( The type of a combination. (Contributed by Mario Carneiro, 7-Oct-2014.)
(New usage is discouraged.) $)
ax-wc $a |- ( F T ) : be $.
$( The type of a combination. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
wc $p |- ( F T ) : be $=
( ax-wc ) ABCDEFG $.
$}
${
ax-ceq.1 $e |- F : ( al -> be ) $.
ax-ceq.2 $e |- T : ( al -> be ) $.
ax-ceq.3 $e |- A : al $.
ax-ceq.4 $e |- B : al $.
$( Equality theorem for combination. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-ceq $a |- ( ( ( = F ) T ) , ( ( = A ) B ) ) |=
( ( = ( F A ) ) ( T B ) ) $.
$}
${
eqcomx.1 $e |- A : al $.
eqcomx.2 $e |- B : al $.
eqcomx.3 $e |- R |= ( ( = A ) B ) $.
$( Commutativity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
eqcomx $p |- R |= ( ( = B ) A ) $=
( ke kc ax-cb1 ax-refl a1i hb ht weq ax-ceq syl2anc wc ax-eqmp ) HBIZBIZH
CIZBIZDUADTCIZDGJZABEKLZHUAIUCIDHTIUBIZUAUGDHHIHIZUDUHDUEAAMNZNHAOZKLGAUI
BCHHUJUJEFPQUFAMBBTUBAUIHBUJERAUIHCUJFREEPQS $.
$}
${
mpbirx.1 $e |- B : bool $.
mpbirx.2 $e |- R |= A $.
mpbirx.3 $e |- R |= ( ( = B ) A ) $.
$( Deduction from equality inference. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
mpbirx $p |- R |= B $=
( hb ax-cb2 eqcomx ax-eqmp ) ABCEGBACDACEHFIJ $.
$}
${
ancoms.1 $e |- ( R , S ) |= T $.
$( Swap the two elements of a context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ancoms $p |- ( S , R ) |= T $=
( kct ax-cb1 wctr wctl simpr simpl syl2anc ) CBAEABBAABCABEDFZGZABLHZIBAM
NJDK $.
$}
${
adantr.1 $e |- R |= T $.
adantr.2 $e |- S : bool $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
adantr $p |- ( R , S ) |= T $=
( kct ax-cb1 simpl syl ) ABFACABCADGEHDI $.
$( Extract an assumption from the context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
adantl $p |- ( S , R ) |= T $=
( adantr ancoms ) ABCABCDEFG $.
$}
${
ct1.1 $e |- R |= S $.
ct1.2 $e |- T : bool $.
$( Introduce a right conjunct. (Contributed by Mario Carneiro,
30-Sep-2023.) $)
ct1 $p |- ( R , T ) |= ( S , T ) $=
( kct adantr ax-cb1 simpr jca ) ACFBCACBDEGACBADHEIJ $.
$( Introduce a left conjunct. (Contributed by Mario Carneiro,
30-Sep-2023.) $)
ct2 $p |- ( T , R ) |= ( T , S ) $=
( kct ax-cb1 simpl adantl jca ) CAFCBCAEBADGHACBDEIJ $.
$}
${
sylan.1 $e |- R |= S $.
sylan.2 $e |- ( S , T ) |= A $.
$( Syllogism inference. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
sylan $p |- ( R , T ) |= A $=
( kct ax-cb1 wctr adantr simpr syl2anc ) ABDGCDBDCECDACDGFHIZJBDCBEHMKFL
$.
$}
${
an32s.1 $e |- ( ( R , S ) , T ) |= A $.
$( Commutation identity for context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
an32s $p |- ( ( R , T ) , S ) |= A $=
( kct ax-cb1 wctl wctr simpl ct1 simpr adantr syl2anc ) ABDFZCFBCFZDOBCBD
BCPDAPDFEGZHZHZPDQIZJBCRIZKOCDBDSTLUAMEN $.
$( Associativity for context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
anasss $p |- ( R , ( S , T ) ) |= A $=
( kct ax-cb1 wctl id ancoms sylan an32s ) CDFBAACBDACBFBCFZDBCMMMDAMDFEGH
IJEKLJ $.
$}
${
anassrs.1 $e |- ( R , ( S , T ) ) |= A $.
$( Associativity for context. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
anassrs $p |- ( ( R , S ) , T ) |= A $=
( kct ax-cb1 wctl wctr simpl adantr simpr ct1 syl2anc ) ABCFZDFBCDFZODBBC
BPABPFEGZHZCDBPQIZHZJCDSIZKOCDBCRTLUAMEN $.
$}
$( The type of a typed variable. (New usage is discouraged.) (Contributed
by Mario Carneiro, 8-Oct-2014.) $)
ax-wv $a |- x : al : al $.
$( The type of a typed variable. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
wv $p |- x : al : al $=
( ax-wv ) ABC $.
${
wl.1 $e |- T : be $.
$( The type of a lambda abstraction. (New usage is discouraged.)
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
ax-wl $a |- \ x : al . T : ( al -> be ) $.
$( The type of a lambda abstraction. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
wl $p |- \ x : al . T : ( al -> be ) $=
( ax-wl ) ABCDEF $.
$}
${
ax-beta.1 $e |- A : be $.
$( Axiom of beta-substitution. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-beta $a |- T. |= ( ( = ( \ x : al . A x : al ) ) A ) $.
ax-distrc.2 $e |- B : al $.
ax-distrc.3 $e |- F : ( be -> ga ) $.
$( Distribution of combination over substitution. (Contributed by Mario
Carneiro, 8-Oct-2014.) $)
ax-distrc $a |- T. |= ( ( = ( \ x : al . ( F A ) B ) )
( ( \ x : al . F B ) ( \ x : al . A B ) ) ) $.
$}
${
$d x R $.
ax-leq.1 $e |- A : be $.
ax-leq.2 $e |- B : be $.
ax-leq.3 $e |- R |= ( ( = A ) B ) $.
$( Equality theorem for abstraction. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-leq $a |- R |= ( ( = \ x : al . A ) \ x : al . B ) $.
$}
${
$d x y $. $d y B $.
ax-distrl.1 $e |- A : ga $.
ax-distrl.2 $e |- B : al $.
$( Distribution of lambda abstraction over substitution. (Contributed by
Mario Carneiro, 8-Oct-2014.) $)
ax-distrl $a |- T. |=
( ( = ( \ x : al . \ y : be . A B ) ) \ y : be . ( \ x : al . A B ) ) $.
$}
${
wov.1 $e |- F : ( al -> ( be -> ga ) ) $.
wov.2 $e |- A : al $.
wov.3 $e |- B : be $.
$( Type of an infix operator. (New usage is discouraged.) (Contributed by
Mario Carneiro, 8-Oct-2014.) $)
ax-wov $a |- [ A F B ] : ga $.
$( Type of an infix operator. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
wov $p |- [ A F B ] : ga $=
( ax-wov ) ABCDEFGHIJ $.
$( Infix operator. This is a simple metamath way of cleaning up the syntax
of all these infix operators to make them a bit more readable than the
curried representation. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
df-ov $a |- T. |= ( ( = [ A F B ] ) ( ( F A ) B ) ) $.
$}
${
dfov1.1 $e |- F : ( al -> ( be -> bool ) ) $.
dfov1.2 $e |- A : al $.
dfov1.3 $e |- B : be $.
${
dfov1.4 $e |- R |= [ A F B ] $.
$( Forward direction of ~ df-ov . (Contributed by Mario Carneiro,
8-Oct-2014.) $)
dfov1 $p |- R |= ( ( F A ) B ) $=
( kbr kc ke ax-cb1 hb df-ov a1i ax-eqmp ) CDEKZECLDLZFJMSLTLFSFJNABOCDE
GHIPQR $.
$}
dfov2.4 $e |- R |= ( ( F A ) B ) $.
$( Reverse direction of ~ df-ov . (Contributed by Mario Carneiro,
8-Oct-2014.) $)
dfov2 $p |- R |= [ A F B ] $=
( kc kbr hb wov ke ax-cb1 df-ov a1i mpbirx ) ECKDKZCDELZFABMCDEGHINJOUAKT
KFTFJPABMCDEGHIQRS $.
$}
${
weqi.1 $e |- A : al $.
weqi.2 $e |- B : al $.
$( Type of an equality. (Contributed by Mario Carneiro, 8-Oct-2014.) $)
weqi $p |- [ A = B ] : bool $=
( hb ke weq wov ) AAFBCGAHDEI $.
$}
${
eqcomi.1 $e |- A : al $.
eqcomi.2 $e |- R |= [ A = B ] $.
$( Deduce equality of types from equality of expressions. (This is
unnecessary but eliminates a lot of hypotheses.)
(New usage is discouraged.) (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-eqtypi $a |- B : al $.
$( Deduce equality of types from equality of expressions. (This is
unnecessary but eliminates a lot of hypotheses.) (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
eqtypi $p |- B : al $=
( ax-eqtypi ) ABCDEFG $.
$( Commutativity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
eqcomi $p |- R |= [ B = A ] $=
( ke weq eqtypi dfov1 eqcomx dfov2 ) AACBGDAHZABCDEFIZEABCDENAABCGDMENFJK
L $.
$}
${
eqtypri.1 $e |- A : al $.
eqtypri.2 $e |- R |= [ B = A ] $.
$( Deduce equality of types from equality of expressions. (This is
unnecessary but eliminates a lot of hypotheses.)
(New usage is discouraged.) (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ax-eqtypri $a |- B : al $.
$( Deduce equality of types from equality of expressions. (This is
unnecessary but eliminates a lot of hypotheses.) (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
eqtypri $p |- B : al $=
( ax-eqtypri ) ABCDEFG $.
$}
${
mpbi.1 $e |- R |= A $.
mpbi.2 $e |- R |= [ A = B ] $.
$( Deduction from equality inference. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
mpbi $p |- R |= B $=
( hb ke weq ax-cb2 eqtypi dfov1 ax-eqmp ) ABCDFFABGCFHACDIZFABCMEJEKL $.
$}
${
eqid.1 $e |- R : bool $.
eqid.2 $e |- A : al $.
$( Reflexivity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
eqid $p |- R |= [ A = A ] $=
( ke weq kc ax-refl a1i dfov2 ) AABBFCAGEEFBHBHCDABEIJK $.
$}
${
ded.1 $e |- ( R , S ) |= T $.
ded.2 $e |- ( R , T ) |= S $.
$( Deduction theorem for equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ded $p |- R |= [ S = T ] $=
( hb ke weq kct ax-cb2 ax-ded dfov2 ) FFBCGAFHBACIEJCABIDJABCDEKL $.
$}
${
dedi.1 $e |- S |= T $.
dedi.2 $e |- T |= S $.
$( Deduction theorem for equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
dedi $p |- T. |= [ S = T ] $=
( kt wtru adantl ded ) EABAEBCFGBEADFGH $.
$}
${
eqtru.1 $e |- R |= A $.
$( If a statement is provable, then it is equivalent to truth.
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
eqtru $p |- R |= [ T. = A ] $=
( kt wtru adantr kct ax-cb1 ax-cb2 wct tru a1i ded ) BDABDACEFDBAGBAABCHA
BCIJKLM $.
$}
${
mpbir.1 $e |- R |= A $.
mpbir.2 $e |- R |= [ B = A ] $.
$( Deduction from equality inference. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
mpbir $p |- R |= B $=
( hb ax-cb2 eqtypri eqcomi mpbi ) ABCDFBACFABCACDGEHEIJ $.
$}
${
ceq12.1 $e |- F : ( al -> be ) $.
ceq12.2 $e |- A : al $.
${
ceq12.3 $e |- R |= [ F = T ] $.
${
ceq12.4 $e |- R |= [ A = B ] $.
$( Equality theorem for combination. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ceq12 $p |- R |= [ ( F A ) = ( T B ) ] $=
( kc ke weq wc ht eqtypi dfov1 ax-ceq syl2anc dfov2 ) BBECLZGDLZMFBNA
BECHIOABGDABPZEGFHJQZACDFIKQZOMUBLUCLFMELGLMCLDLUDUDEGMFUDNHUEJRAACDM
FANIUFKRABCDEGHUEIUFSTUA $.
$}
$( Equality theorem for combination. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ceq1 $p |- R |= [ ( F A ) = ( T A ) ] $=
( ke kbr ax-cb1 eqid ceq12 ) ABCCDEFGHIACEDFJKEILHMN $.
$}
ceq2.3 $e |- R |= [ A = B ] $.
$( Equality theorem for combination. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
ceq2 $p |- R |= [ ( F A ) = ( F B ) ] $=
( ht ke kbr ax-cb1 eqid ceq12 ) ABCDEFEGHABJEFCDKLFIMGNIO $.
$}
${
$d x R $.
leq.1 $e |- A : be $.
leq.2 $e |- R |= [ A = B ] $.
$( Equality theorem for lambda abstraction. (Contributed by Mario
Carneiro, 8-Oct-2014.) $)
leq $p |- R |= [ \ x : al . A = \ x : al . B ] $=
( ht kl ke weq wl eqtypi dfov1 ax-leq dfov2 ) ABIZRACDJACEJKFRLABCDGMABCE
BDEFGHNZMABCDEFGSBBDEKFBLGSHOPQ $.
$}
${
beta.1 $e |- A : be $.
$( Axiom of beta-substitution. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
beta $p |- T. |= [ ( \ x : al . A x : al ) = A ] $=
( kl tv kc ke kt weq wl wv wc ax-beta dfov2 ) BBACDFZACGZHDIJBKABQRABCDEL
ACMNEABCDEOP $.
$}
${
distrc.1 $e |- F : ( be -> ga ) $.
distrc.2 $e |- A : be $.
distrc.3 $e |- B : al $.
$( Distribution of combination over substitution. (Contributed by Mario
Carneiro, 8-Oct-2014.) $)
distrc $p |- T. |= [ ( \ x : al . ( F A ) B ) =
( ( \ x : al . F B ) ( \ x : al . A B ) ) ] $=
( kc kl ke kt weq wc wl ht ax-distrc dfov2 ) CCADGEKZLZFKADGLZFKZADELZFKZ
KMNCOACUBFACDUABCGEHIPQJPBCUDUFABCRZUCFAUGDGHQJPABUEFABDEIQJPPABCDEFGIJHS
T $.
$}
${
$d x y $. $d y B $.
distrl.1 $e |- A : ga $.
distrl.2 $e |- B : al $.
$( Distribution of lambda abstraction over substitution. (Contributed by
Mario Carneiro, 8-Oct-2014.) $)
distrl $p |- T. |=
[ ( \ x : al . \ y : be . A B ) = \ y : be . ( \ x : al . A B ) ] $=
( ht kl kc ke kt weq wl wc ax-distrl dfov2 ) BCJZTADBEFKZKZGLBEADFKZGLZKM
NTOATUBGATDUABCEFHPPIQBCEUDACUCGACDFHPIQPABCDEFGHIRS $.
$}
${
eqtri.1 $e |- A : al $.
eqtri.2 $e |- R |= [ A = B ] $.
eqtri.3 $e |- R |= [ B = C ] $.
$( Transitivity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
eqtri $p |- R |= [ A = C ] $=
( ke weq eqtypi kc dfov1 hb ht wc ceq2 mpbi dfov2 ) AABDIEAJZFACDEABCEFGK
ZHKIBLZCLUBDLEAABCIETFUAGMANCDUBEAANOIBTFPUAHQRS $.
$}
${
3eqtr4i.1 $e |- A : al $.
3eqtr4i.2 $e |- R |= [ A = B ] $.
${
3eqtr4i.3 $e |- R |= [ S = A ] $.
3eqtr4i.4 $e |- R |= [ T = B ] $.
$( Transitivity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
3eqtr4i $p |- R |= [ S = T ] $=
( eqtypri eqtypi eqcomi eqtri ) AEBFDABEDGIKIABCFDGHAFCDACFDABCDGHLJKJM
NN $.
$}
3eqtr3i.3 $e |- R |= [ A = S ] $.
3eqtr3i.4 $e |- R |= [ B = T ] $.
$( Transitivity of equality. (Contributed by Mario Carneiro,
7-Oct-2014.) $)
3eqtr3i $p |- R |= [ S = T ] $=
( eqcomi eqtypi 3eqtr4i ) ABCDEFGHABEDGIKACFDABCDGHLJKM $.
$}
${
oveq.1 $e |- F : ( al -> ( be -> ga ) ) $.
oveq.2 $e |- A : al $.
oveq.3 $e |- B : be $.
${
oveq123.4 $e |- R |= [ F = S ] $.
oveq123.5 $e |- R |= [ A = C ] $.
oveq123.6 $e |- R |= [ B = T ] $.
$( Equality theorem for binary operation. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
oveq123 $p |- R |= [ [ A F B ] = [ C S T ] ] $=
( kc kbr wc ke ht ceq12 weq wov ax-cb1 df-ov a1i dfov2 eqtypi 3eqtr4i )
CGDQZEQZIFQZJQZHDEGRZFJIRZBCUKEABCUAZGDKLSZMSZBCEJUKHUMURMAUQDFGHIKLNOU
BPUBCCUOULTHCUCZABCDEGKLMUDUSTUOQULQHGITRHNUEZABCDEGKLMUFUGUHCCUPUNTHUT
ABCFJIAUQUAGIHKNUIZADFHLOUIZBEJHMPUIZUDBCUMJAUQIFVBVCSVDSTUPQUNQHVAABCF
JIVBVCVDUFUGUHUJ $.
$}
${
oveq1.4 $e |- R |= [ A = C ] $.
$( Equality theorem for binary operation. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
oveq1 $p |- R |= [ [ A F B ] = [ C F B ] ] $=
( ht ke kbr ax-cb1 eqid oveq123 ) ABCDEFGHGEIJKABCMMGHDFNOHLPZIQLBEHSKQ
R $.
oveq12.5 $e |- R |= [ B = T ] $.
$( Equality theorem for binary operation. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
oveq12 $p |- R |= [ [ A F B ] = [ C F T ] ] $=
( ht ke kbr ax-cb1 eqid oveq123 ) ABCDEFGHGIJKLABCOOGHDFPQHMRJSMNT $.
$}
${
oveq2.4 $e |- R |= [ B = T ] $.
$( Equality theorem for binary operation. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
oveq2 $p |- R |= [ [ A F B ] = [ A F T ] ] $=
( ke kbr ax-cb1 eqid oveq12 ) ABCDEDFGHIJKADGEHMNGLOJPLQ $.
$}
${
oveq.4 $e |- R |= [ F = S ] $.
$( Equality theorem for binary operation. (Contributed by Mario
Carneiro, 7-Oct-2014.) $)
oveq $p |- R |= [ [ A F B ] = [ A S B ] ] $=
( ke kbr ax-cb1 eqid oveq123 ) ABCDEDFGHEIJKLADGFHMNGLOZJPBEGRKPQ $.
$}
$}
${
ax-hbl1.1 $e |- A : ga $.
ax-hbl1.2 $e |- B : al $.
$( ` x ` is bound in ` \ x A ` . (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-hbl1 $a |- T. |= [ ( \ x : al . \ x : be . A B ) = \ x : be . A ] $.
hbl1.3 $e |- R : bool $.
$( Inference form of ~ ax-hbl1 . (Contributed by Mario Carneiro,
8-Oct-2014.) $)
hbl1 $p |- R |= [ ( \ x : al . \ x : be . A B ) = \ x : be . A ] $=
( kl kc ke kbr ax-hbl1 a1i ) ADBDEKZKFLQMNGJABCDEFHIOP $.
$}
${
$d x A $.
ax-17.1 $e |- A : be $.
ax-17.2 $e |- B : al $.
$( If ` x ` does not appear in ` A ` , then any substitution to ` A `
yields ` A ` again, i.e. ` \ x A ` is a constant function. (Contributed
by Mario Carneiro, 8-Oct-2014.) $)
ax-17 $a |- T. |= [ ( \ x : al . A B ) = A ] $.
a17i.3 $e |- R : bool $.
$( Inference form of ~ ax-17 . (Contributed by Mario Carneiro,
8-Oct-2014.) $)
a17i $p |- R |= [ ( \ x : al . A B ) = A ] $=
( kl kc ke kbr ax-17 a1i ) ACDJEKDLMFIABCDEGHNO $.
$}
${
$d x R $.
hbxfr.1 $e |- T : be $.
hbxfr.2 $e |- B : al $.
${
hbxfrf.3 $e |- R |= [ T = A ] $.
hbxfrf.4 $e |- ( S , R ) |= [ ( \ x : al . A B ) = A ] $.
$( Transfer a hypothesis builder to an equivalent expression.
(Contributed by Mario Carneiro, 8-Oct-2014.) $)
hbxfrf $p |- ( S , R ) |= [ ( \ x : al . T B ) = T ] $=
( kl kc kct eqtypi wl ke kbr adantl wc leq ceq1 ax-cb1 wctl 3eqtr4i ) B
ACDMZENZDGFOZACHMZENZHABUGEABCDBHDFIKPQJUALFGUKUHRSABEUJFUGABCHIQJABCHD
FIKUBUCGFUHDRSUILUDUEZTFGHDRSKULTUF $.
$}
hbxfr.3 $e |- R |= [ T = A ] $.
hbxfr.4 $e |- R |= [ ( \ x : al . A B ) = A ] $.
$( Transfer a hypothesis builder to an equivalent expression. (Contributed
by Mario Carneiro, 8-Oct-2014.) $)
hbxfr $p |- R |= [ ( \ x : al . T B ) = T ] $=
( kl kc ke kbr ax-cb1 id adantr hbxfrf syl2anc ) ACGLEMGNOFFFFGDNOFJPZQZU
BABCDEFFGHIJFFACDLEMDNOKUARST $.
$}
${
$d x R $.
hbth.1 $e |- B : al $.
hbth.2 $e |- R |= A $.
$( Hypothesis builder for a theorem. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
hbth $p |- R |= [ ( \ x : al . A B ) = A ] $=
( hb kt ax-cb2 wtru eqtru eqcomi ax-cb1 a17i hbxfr ) AHBIDECCEGJFHICEKCEG
LMAHBIDEKFCEGNOP $.
$}
${
hbc.1 $e |- F : ( be -> ga ) $.
hbc.2 $e |- A : be $.
hbc.3 $e |- B : al $.
hbc.4 $e |- R |= [ ( \ x : al . F B ) = F ] $.
hbc.5 $e |- R |= [ ( \ x : al . A B ) = A ] $.
$( Hypothesis builder for combination. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
hbc $p |- R |= [ ( \ x : al . ( F A ) B ) = ( F A ) ] $=
( kc kl wc wl ke kbr ax-cb1 distrc a1i ht eqtypri ceq12 eqtri ) CADGENZOZ
FNZADGOZFNZADEOFNZNZUGHACUHFACDUGBCGEIJPQKPUIUMRSHUKGRSHLTABCDEFGIJKUAUBB
CULEUKHGABCUCZUJFAUNDGIQKPBEULHJMUDLMUEUF $.
$}
${
hbov.1 $e |- F : ( be -> ( ga -> de ) ) $.
hbov.2 $e |- A : be $.
hbov.3 $e |- B : al $.
hbov.4 $e |- C : ga $.
hbov.5 $e |- R |= [ ( \ x : al . F B ) = F ] $.
hbov.6 $e |- R |= [ ( \ x : al . A B ) = A ] $.
hbov.7 $e |- R |= [ ( \ x : al . C B ) = C ] $.
$( Hypothesis builder for binary operation. (Contributed by Mario
Carneiro, 8-Oct-2014.) $)
hbov $p |- R |= [ ( \ x : al . [ A F C ] B ) = [ A F C ] ] $=
( kt kbr kc kl ke ax-cb1 trud wov weq ht wc df-ov dfov2 hbc adantr hbxfrf
wtru mpdan ) JRAEFHISZUAGTUPUBSJAEIUAGTIUBSJOUCUDADEIFTZHTZGRJUPBCDFHIKLN
UEZMDDUPURUBRDUFUSCDUQHBCDUGZIFKLUHZNUHBCDFHIKLNUIUJJRAEURUAGTURUBSACDEHG
UQJVANMABUTEFGIJKLMOPUKQUKUNULUMUO $.
$}
${
$d x y $. $d y B $. $d y R $.
hbl.1 $e |- A : ga $.
hbl.2 $e |- B : al $.
hbl.3 $e |- R |= [ ( \ x : al . A B ) = A ] $.
$( Hypothesis builder for lambda abstraction. (Contributed by Mario
Carneiro, 8-Oct-2014.) $)
hbl $p |- R |= [ ( \ x : al . \ y : be . A B ) = \ y : be . A ] $=
( ht kl kc wl wc ke kbr ax-cb1 distrl a1i leq eqtri ) BCLZADBEFMZMZGNZBEA
DFMZGNZMZUEHAUDUFGAUDDUEBCEFIOOJPUGUJQRHUIFQRHKSABCDEFGIJTUABCEUIFHACUHGA
CDFIOJPKUBUC $.
$}
${
$d x y $. $d y B $. $d y S $.
ax-inst.1 $e |- R |= A $.
ax-inst.2 $e |- T. |= [ ( \ x : al . B y : al ) = B ] $.
ax-inst.3 $e |- T. |= [ ( \ x : al . S y : al ) = S ] $.
ax-inst.4 $e |- [ x : al = C ] |= [ A = B ] $.
ax-inst.5 $e |- [ x : al = C ] |= [ R = S ] $.
$( Instantiate a theorem with a new term. The second and third hypotheses
are the HOL equivalent of set.mm "effectively not free in" predicate
(see set.mm's ax-17, or ~ ax17m ). (Contributed by Mario Carneiro,
8-Oct-2014.) $)
ax-inst $a |- S |= B $.
$}
${
$d x y R $. $d y B $.
insti.1 $e |- C : al $.
insti.2 $e |- B : bool $.
insti.3 $e |- R |= A $.
insti.4 $e |- T. |= [ ( \ x : al . B y : al ) = B ] $.
insti.5 $e |- [ x : al = C ] |= [ A = B ] $.
$( Instantiate a theorem with a new term. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
insti $p |- R |= B $=
( hb tv ax-cb1 wv ax-17 ke kbr eqid ax-inst ) ABCDEFGGJKAMBGACNDGJOZACPQL
MGABNFRSZDERSUCLOUBTUA $.
$}
${
$d y A $. $d y B $. $d y C $. $d x y al $.
clf.1 $e |- A : be $.
clf.2 $e |- C : al $.
clf.3 $e |- [ x : al = C ] |= [ A = B ] $.
clf.4 $e |- T. |= [ ( \ x : al . B y : al ) = B ] $.
clf.5 $e |- T. |= [ ( \ x : al . C y : al ) = C ] $.
$( Evaluate a lambda expression. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
clf $p |- T. |= [ ( \ x : al . A C ) = B ] $=
( kl tv kc ke kbr kt wc hb wl eqtypi weqi ax-cb1 beta a1i wv ht a17i hbl1
weq hbc hbov id ceq2 oveq12 insti ) ACDACEMZACNZOZEPQZURGOZFPQGRIBVBFABUR
GABCEHUAZISZBEFUSGPQZHJUBZUCVARACFMADNZOFPQRKUDZABCEHUEUFABBTCVBVGFPRBUKZ
VDADUGZVFABBTUHUHCPVGRVIVJVHUIAABCGVGURRVCIVJAABCEVGRHVJVHUJLULKUMBBTUTEV
BPVEFVIABURUSVCACUGZSHABUSGURVEVCVKVEAUSGVKIUCUNUOJUPUQ $.
$}
${
$d y A $. $d x y B $. $d x y C $. $d x y al $.
cl.1 $e |- A : be $.
cl.2 $e |- C : al $.
cl.3 $e |- [ x : al = C ] |= [ A = B ] $.
$( Evaluate a lambda expression. (Contributed by Mario Carneiro,
8-Oct-2014.) $)
cl $p |- T. |= [ ( \ x : al . A C ) = B ] $=
( vy tv ke kbr eqtypi wv ax-17 clf ) ABCJDEFGHIABCEAJKZBDEACKFLMGINAJOZPA