Nuprl Lemma : fpf-compatible-join-cap
∀[A:Type]. ∀[eq:EqDecider(A)]. ∀[B:A ⟶ Type]. ∀[f,g:a:A fp-> B[a]]. ∀[x:A]. ∀[z:B[x]].
  f ⊕ g(x)?z = g(x)?f(x)?z ∈ B[x] supposing f || g
Proof
Definitions occuring in Statement : 
fpf-join: f ⊕ g
, 
fpf-compatible: f || g
, 
fpf-cap: f(x)?z
, 
fpf: a:A fp-> B[a]
, 
deq: EqDecider(T)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
fpf-compatible: f || g
, 
fpf-cap: f(x)?z
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
squash: ↓T
, 
true: True
, 
guard: {T}
, 
rev_implies: P 
⇐ Q
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
not: ¬A
, 
cand: A c∧ B
, 
top: Top
Lemmas referenced : 
fpf-compatible_wf, 
fpf_wf, 
deq_wf, 
fpf-dom_wf, 
fpf-join_wf, 
top_wf, 
subtype-fpf2, 
fpf-join-dom, 
equal-wf-T-base, 
bool_wf, 
assert_wf, 
bnot_wf, 
not_wf, 
eqtt_to_assert, 
equal_wf, 
squash_wf, 
true_wf, 
fpf-join-ap-left, 
fpf-ap_wf, 
subtype_rel_self, 
iff_weakening_equal, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
istype-assert, 
uiff_transitivity, 
assert_of_bnot, 
fpf-join-ap-sq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
hypothesis, 
universeIsType, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality_alt, 
applyEquality, 
inhabitedIsType, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
because_Cache, 
independent_isectElimination, 
lambdaFormation_alt, 
Error :memTop, 
dependent_functionElimination, 
productElimination, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
baseClosed, 
unionElimination, 
equalityElimination, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
instantiate, 
dependent_pairFormation_alt, 
equalityIstype, 
promote_hyp, 
cumulativity, 
voidElimination, 
unionIsType, 
independent_pairFormation, 
universeEquality, 
voidEquality, 
isect_memberEquality, 
lambdaFormation, 
functionExtensionality, 
lambdaEquality, 
inrFormation_alt, 
inlFormation_alt
Latex:
\mforall{}[A:Type].  \mforall{}[eq:EqDecider(A)].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[f,g:a:A  fp->  B[a]].  \mforall{}[x:A].  \mforall{}[z:B[x]].
    f  \moplus{}  g(x)?z  =  g(x)?f(x)?z  supposing  f  ||  g
Date html generated:
2020_05_20-AM-09_03_18
Last ObjectModification:
2019_12_26-PM-04_07_17
Theory : finite!partial!functions
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