Nuprl Lemma : all-accessible-iff-weak-TI
∀[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].  (∀t:T. accessible(T;x,y.R[x;y];t) 
⇐⇒ ∀[P:T ⟶ ℙ]. weak-TI(T;x,y.R[y;x];t.P[t]))
Proof
Definitions occuring in Statement : 
accessible: accessible(T;x,y.R[x; y];t)
, 
weak-TI: weak-TI(T;x,y.R[x; y];t.Q[t])
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
weak-TI: weak-TI(T;x,y.R[x; y];t.Q[t])
Lemmas referenced : 
all-accessible-iff-induction
Rules used in proof : 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
hypothesis
Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
    (\mforall{}t:T.  accessible(T;x,y.R[x;y];t)  \mLeftarrow{}{}\mRightarrow{}  \mforall{}[P:T  {}\mrightarrow{}  \mBbbP{}].  weak-TI(T;x,y.R[y;x];t.P[t]))
Date html generated:
2016_05_14-AM-06_18_52
Last ObjectModification:
2015_12_26-PM-00_02_41
Theory : co-recursion
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