Nuprl Lemma : equal-partial
∀[T:Type]. ∀[x,y:partial(T)].  uiff(x = y ∈ partial(T);uiff((x)↓;(y)↓) ∧ ((x)↓ ⇒ (x = y ∈ T))) supposing value-type(T)
Proof
Definitions occuring in Statement : 
partial: partial(T), 
value-type: value-type(T), 
has-value: (a)↓, 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
uimplies: b supposing a, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
member: t ∈ T, 
has-value: (a)↓, 
implies: P ⇒ Q, 
prop: ℙ, 
respects-equality: respects-equality(S;T), 
all: ∀x:A. B[x], 
cand: A c∧ B, 
squash: ↓T, 
subtype_rel: A ⊆r B, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
label: ...$L... t, 
true: True, 
partial: partial(T), 
quotient: x,y:A//B[x; y], 
so_lambda: λ2x y.t[x; y], 
base-partial: base-partial(T), 
so_apply: x[s1;s2], 
equiv_rel: EquivRel(T;x,y.E[x; y]), 
trans: Trans(T;x,y.E[x; y]), 
per-partial: per-partial(T;x;y)
Lemmas referenced : 
has-value_wf-partial, 
respects-equality-partial, 
partial_wf, 
value-type_wf, 
istype-universe, 
termination, 
squash_wf, 
subtype_rel_self, 
iff_weakening_equal, 
equal_wf, 
true_wf, 
termination-equality, 
quotient-member-eq, 
per-partial_wf, 
per-partial-equiv_rel, 
base-partial_wf, 
has-value_wf_base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
independent_pairFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairEquality, 
Error :isect_memberEquality_alt, 
isectElimination, 
hypothesisEquality, 
axiomSqleEquality, 
hypothesis, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
Error :lambdaEquality_alt, 
dependent_functionElimination, 
axiomEquality, 
Error :functionIsTypeImplies, 
Error :equalityIstype, 
because_Cache, 
Error :productIsType, 
Error :isectIsType, 
Error :universeIsType, 
extract_by_obid, 
independent_isectElimination, 
Error :functionIsType, 
independent_functionElimination, 
instantiate, 
universeEquality, 
Error :lambdaFormation_alt, 
applyEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
promote_hyp, 
natural_numberEquality, 
pointwiseFunctionalityForEquality, 
pertypeElimination, 
setElimination, 
rename, 
sqequalBase
Latex:
\mforall{}[T:Type]
    \mforall{}[x,y:partial(T)].    uiff(x  =  y;uiff((x)\mdownarrow{};(y)\mdownarrow{})  \mwedge{}  ((x)\mdownarrow{}  {}\mRightarrow{}  (x  =  y)))  supposing  value-type(T)
Date html generated:
2019_06_20-PM-00_34_01
Last ObjectModification:
2018_11_23-PM-01_15_52
Theory : partial_1
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