Nuprl Lemma : fix_wf_coW_parameter
∀[P:Type]. ∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[G:⋂W:𝕌'. ((P ⟶ W) ⟶ P ⟶ (a:A × (B[a] ⟶ W)))]. ∀[p:P].
  (fix(G) p ∈ coW(A;a.B[a]))
Proof
Definitions occuring in Statement : 
coW: coW(A;a.B[a]), 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
member: t ∈ T, 
apply: f a, 
fix: fix(F), 
isect: ⋂x:A. B[x], 
function: x:A ⟶ B[x], 
product: x:A × B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
isect2: T1 ⋂ T2, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
top: Top, 
bfalse: ff, 
ext-eq: A ≡ B, 
and: P ∧ Q
Lemmas referenced : 
fix_wf_corec_parameter, 
top_wf, 
bool_wf, 
coW-corec
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
applyEquality, 
hypothesis, 
sqequalHypSubstitution, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
hypothesisEquality, 
isect_memberEquality, 
isectElimination, 
thin, 
because_Cache, 
isectEquality, 
universeEquality, 
cumulativity, 
functionEquality, 
productEquality, 
instantiate, 
extract_by_obid, 
lambdaEquality, 
unionElimination, 
equalityElimination, 
functionExtensionality, 
voidElimination, 
voidEquality, 
productElimination
Latex:
\mforall{}[P:Type].  \mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[G:\mcap{}W:\mBbbU{}'.  ((P  {}\mrightarrow{}  W)  {}\mrightarrow{}  P  {}\mrightarrow{}  (a:A  \mtimes{}  (B[a]  {}\mrightarrow{}  W)))].  \mforall{}[p:P].
    (fix(G)  p  \mmember{}  coW(A;a.B[a]))
 Date html generated: 
2019_06_20-PM-00_56_05
 Last ObjectModification: 
2019_01_02-PM-01_32_43
Theory : co-recursion-2
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