Nuprl Lemma : trivial-same-context-set
∀X,Y:?CubicalContext.
  ((Y = bind-provision(X;ctxt.OK(ctxt)) ∈ ?CubicalContext)
  
⇒ context-ok(X)
  
⇒ {(X = Y ∈ ?CubicalContext) ∧ (context-set(X) = context-set(Y) ∈ CubicalSet''')})
Proof
Definitions occuring in Statement : 
context-set: context-set(ctxt)
, 
context-ok: context-ok(ctxt)
, 
cubical-context: ?CubicalContext
, 
cubical_set: CubicalSet
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
true: True
, 
equal: s = t ∈ T
, 
bind-provision: bind-provision(x;t.f[t])
, 
provision: provision(ok; v)
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
and: P ∧ Q
, 
squash: ↓T
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
uimplies: b supposing a
, 
true: True
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cubical-context: ?CubicalContext
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
trivial-same-cubical-context, 
cubical-context_wf, 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
cubical_set_wf, 
context-set_wf, 
context-ok_wf, 
subtype_rel_self, 
iff_weakening_equal, 
bind-provision_wf, 
cubical_context_wf, 
provision_wf, 
istype-true, 
allowed_wf, 
allow_wf
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
inhabitedIsType, 
universeIsType, 
independent_pairFormation, 
applyEquality, 
instantiate, 
lambdaEquality_alt, 
imageElimination, 
isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
independent_isectElimination, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
natural_numberEquality, 
productElimination, 
equalityIstype, 
cumulativity, 
isect_memberEquality_alt, 
setElimination, 
rename, 
setIsType, 
productIsType
Latex:
\mforall{}X,Y:?CubicalContext.
    ((Y  =  bind-provision(X;ctxt.OK(ctxt)))
    {}\mRightarrow{}  context-ok(X)
    {}\mRightarrow{}  \{(X  =  Y)  \mwedge{}  (context-set(X)  =  context-set(Y))\})
Date html generated:
2020_05_20-PM-08_07_19
Last ObjectModification:
2020_05_18-PM-03_02_49
Theory : cubical!type!theory
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