Nuprl Lemma : fpf-join-dom
∀[A:Type]. ∀[B:A ⟶ Type].
  ∀eq:EqDecider(A). ∀f,g:a:A fp-> B[a]. ∀x:A.  (↑x ∈ dom(f ⊕ g) 
⇐⇒ (↑x ∈ dom(f)) ∨ (↑x ∈ dom(g)))
Proof
Definitions occuring in Statement : 
fpf-join: f ⊕ g
, 
fpf-dom: x ∈ dom(f)
, 
fpf: a:A fp-> B[a]
, 
deq: EqDecider(T)
, 
assert: ↑b
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
fpf-dom: x ∈ dom(f)
, 
fpf-join: f ⊕ g
, 
fpf: a:A fp-> B[a]
, 
pi1: fst(t)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
top: Top
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
iff: P 
⇐⇒ Q
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
bfalse: ff
, 
or: P ∨ Q
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
, 
sq_type: SQType(T)
, 
guard: {T}
, 
false: False
, 
not: ¬A
, 
cand: A c∧ B
, 
true: True
, 
so_apply: x[s]
Lemmas referenced : 
deq-member_wf, 
pi1_wf_top, 
list_wf, 
bool_wf, 
eqtt_to_assert, 
assert-deq-member, 
l_member_wf, 
or_wf, 
false_wf, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
true_wf, 
member_filter, 
bnot_wf, 
assert_wf, 
filter_wf5, 
iff_wf, 
member_append, 
append_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_pairEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
because_Cache, 
dependent_functionElimination, 
independent_functionElimination, 
independent_pairFormation, 
inlFormation, 
productEquality, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
inrFormation, 
natural_numberEquality, 
addLevel, 
orFunctionality, 
lambdaEquality, 
setElimination, 
rename, 
setEquality, 
impliesFunctionality, 
orLevelFunctionality, 
functionEquality, 
applyEquality, 
functionExtensionality, 
universeEquality
Latex:
\mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].
    \mforall{}eq:EqDecider(A).  \mforall{}f,g:a:A  fp->  B[a].  \mforall{}x:A.    (\muparrow{}x  \mmember{}  dom(f  \moplus{}  g)  \mLeftarrow{}{}\mRightarrow{}  (\muparrow{}x  \mmember{}  dom(f))  \mvee{}  (\muparrow{}x  \mmember{}  dom(g)))
Date html generated:
2018_05_21-PM-09_21_26
Last ObjectModification:
2018_02_09-AM-10_18_16
Theory : finite!partial!functions
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