Nuprl Lemma : fset-constrained-image-singleton
∀[eqt,eqa:Top]. ∀[T,A:Type]. ∀[f:T ⟶ A]. ∀[P:A ⟶ 𝔹]. ∀[x:T].  (f"({x}) s.t. P ~ if P (f x) then {f x} else {} fi )
Proof
Definitions occuring in Statement : 
fset-constrained-image: f"(s) s.t. P
, 
empty-fset: {}
, 
fset-singleton: {x}
, 
ifthenelse: if b then t else f fi 
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
fset-singleton: {x}
, 
fset-constrained-image: f"(s) s.t. P
, 
f-union: f-union(domeq;rngeq;s;x.g[x])
, 
all: ∀x:A. B[x]
, 
top: Top
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
fset-union: x ⋃ y
, 
l-union: as ⋃ bs
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
empty-fset: {}
Lemmas referenced : 
list_accum_cons_lemma, 
list_accum_nil_lemma, 
bool_wf, 
eqtt_to_assert, 
reduce_cons_lemma, 
reduce_nil_lemma, 
insert_nil_lemma, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
top_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
hypothesis, 
applyEquality, 
functionExtensionality, 
hypothesisEquality, 
cumulativity, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
because_Cache, 
independent_functionElimination, 
sqequalAxiom, 
functionEquality, 
universeEquality
Latex:
\mforall{}[eqt,eqa:Top].  \mforall{}[T,A:Type].  \mforall{}[f:T  {}\mrightarrow{}  A].  \mforall{}[P:A  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[x:T].
    (f"(\{x\})  s.t.  P  \msim{}  if  P  (f  x)  then  \{f  x\}  else  \{\}  fi  )
Date html generated:
2017_04_17-AM-09_21_11
Last ObjectModification:
2017_02_27-PM-05_23_57
Theory : finite!sets
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