Nuprl Lemma : has-value-try-iff
∀[t,n,B:Base].
  uiff((t?n:v.B[v])↓;↓((t)↓ ∧ (t?n:v.B[v] ~ t)) ∨ (∃u:Base. ((t ~ exception(n; u)) ∧ (t?n:v.B[v] ~ B[u]) ∧ (B[u])↓)))
Proof
Definitions occuring in Statement : 
has-value: (a)↓
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
or: P ∨ Q
, 
and: P ∧ Q
, 
base: Base
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
squash: ↓T
, 
prop: ℙ
, 
has-value: (a)↓
, 
sq_stable: SqStable(P)
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
exists: ∃x:A. B[x]
Lemmas referenced : 
has-value-try, 
has-value_wf_base, 
squash_wf, 
or_wf, 
exists_wf, 
base_wf, 
sq_stable__has-value
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
independent_pairFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
baseApply, 
closedConclusion, 
baseClosed, 
independent_isectElimination, 
hypothesis, 
imageElimination, 
imageMemberEquality, 
axiomSqleEquality, 
productEquality, 
sqequalIntensionalEquality, 
lambdaEquality, 
productElimination, 
independent_pairEquality, 
isect_memberEquality, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
unionElimination
Latex:
\mforall{}[t,n,B:Base].
    uiff((t?n:v.B[v])\mdownarrow{};\mdownarrow{}((t)\mdownarrow{}  \mwedge{}  (t?n:v.B[v]  \msim{}  t))
                                            \mvee{}  (\mexists{}u:Base.  ((t  \msim{}  exception(n;  u))  \mwedge{}  (t?n:v.B[v]  \msim{}  B[u])  \mwedge{}  (B[u])\mdownarrow{})))
Date html generated:
2017_02_20-AM-10_46_27
Last ObjectModification:
2017_01_25-PM-07_01_20
Theory : call!by!value_1
Home
Index