Nuprl Lemma : deq-f-subset_wf
∀[T:Type]. ∀[eq:EqDecider(T)].  (deq-f-subset(eq) ∈ {d:fset(T) ⟶ fset(T) ⟶ 𝔹| ∀x,y:fset(T).  (x ⊆ y 
⇐⇒ ↑(d x y))} )
Proof
Definitions occuring in Statement : 
deq-f-subset: deq-f-subset(eq)
, 
f-subset: xs ⊆ ys
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
deq-f-subset: deq-f-subset(eq)
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
decidable__f-subset, 
decidable__all_fset, 
decidable_functionality, 
iff_preserves_decidability, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
top: Top
, 
uimplies: b supposing a
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
iff_weakening_uiff, 
decidable__fset-member, 
assert-deq-fset-member, 
decidable__assert, 
fset-all-iff, 
fset-null: fset-null(s)
, 
null: null(as)
, 
fset-filter: {x ∈ s | P[x]}
, 
filter: filter(P;l)
, 
reduce: reduce(f;k;as)
, 
list_ind: list_ind, 
ifthenelse: if b then t else f fi 
, 
bnot: ¬bb
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
isl: isl(x)
, 
rev_implies: P 
⇐ Q
, 
false: False
, 
not: ¬A
, 
bfalse: ff
, 
true: True
, 
btrue: tt
, 
assert: ↑b
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
subtype_rel: A ⊆r B
Lemmas referenced : 
deq_wf, 
lifting-strict-spread, 
istype-void, 
strict4-apply, 
lifting-strict-decide, 
strict4-decide, 
iff_wf, 
all_wf, 
assert_wf, 
equal_wf, 
not_wf, 
isl_wf, 
f-subset_wf, 
decidable_wf, 
fset_wf, 
decidable__f-subset, 
decidable__all_fset, 
decidable_functionality, 
iff_preserves_decidability, 
iff_weakening_uiff, 
decidable__fset-member, 
assert-deq-fset-member, 
decidable__assert, 
fset-all-iff
Rules used in proof : 
universeEquality, 
because_Cache, 
isect_memberEquality, 
hypothesisEquality, 
cumulativity, 
thin, 
isectElimination, 
extract_by_obid, 
equalitySymmetry, 
equalityTransitivity, 
axiomEquality, 
sqequalRule, 
hypothesis, 
sqequalHypSubstitution, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
baseClosed, 
Error :isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination, 
functionExtensionality, 
natural_numberEquality, 
unionElimination, 
independent_pairFormation, 
independent_functionElimination, 
dependent_functionElimination, 
lambdaFormation, 
functionEquality, 
isectEquality, 
instantiate, 
applyEquality, 
lambdaEquality, 
dependent_set_memberEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].
    (deq-f-subset(eq)  \mmember{}  \{d:fset(T)  {}\mrightarrow{}  fset(T)  {}\mrightarrow{}  \mBbbB{}|  \mforall{}x,y:fset(T).    (x  \msubseteq{}  y  \mLeftarrow{}{}\mRightarrow{}  \muparrow{}(d  x  y))\}  )
Date html generated:
2019_06_20-PM-01_59_21
Last ObjectModification:
2019_01_09-PM-03_28_01
Theory : finite!sets
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