Nuprl Lemma : coW-equiv-iff
∀[A:𝕌']
  ∀B:A ⟶ Type. ∀w,w':coW(A;a.B[a]).
    (coW-equiv(a.B[a];w;w') 
⇐⇒ ∀z:coW(A;a.B[a]). (coWmem(a.B[a];z;w) 
⇐⇒ coWmem(a.B[a];z;w')))
Proof
Definitions occuring in Statement : 
coWmem: coWmem(a.B[a];z;w)
, 
coW-equiv: coW-equiv(a.B[a];w;w')
, 
coW: coW(A;a.B[a])
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
label: ...$L... t
, 
copath-cons: copath-cons(b;x)
, 
coPathAgree: coPathAgree(a.B[a];n;w;p;q)
, 
copathAgree: copathAgree(a.B[a];w;x;y)
, 
sg-legal2: Legal2(x;y)
, 
top: Top
, 
less_than': less_than'(a;b)
, 
le: A ≤ B
, 
ext-eq: A ≡ B
, 
exists: ∃x:A. B[x]
, 
coW-dom: coW-dom(a.B[a];w)
, 
coW-item: coW-item(w;b)
, 
coWmem: coWmem(a.B[a];z;w)
, 
bfalse: ff
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
subtract: n - m
, 
eq_int: (i =z j)
, 
coPath: coPath(a.B[a];w;n)
, 
copath: copath(a.B[a];w)
, 
squash: ↓T
, 
sq_type: SQType(T)
, 
uimplies: b supposing a
, 
true: True
, 
false: False
, 
not: ¬A
, 
guard: {T}
, 
cand: A c∧ B
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
nat: ℕ
, 
subtype_rel: A ⊆r B
, 
copath-nil: ()
, 
copath-length: copath-length(p)
, 
sg-init: InitialPos(g)
, 
pi2: snd(t)
, 
sg-legal1: Legal1(x;y)
, 
pi1: fst(t)
, 
sg-pos: Pos(g)
, 
coW-game: coW-game(a.B[a];w;w')
, 
coW-equiv: coW-equiv(a.B[a];w;w')
, 
rev_implies: P 
⇐ Q
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
coW-game-step-isom, 
isom-preserves-win2, 
sg-normalize_wf, 
sg-normalize-win2, 
simple-game_wf, 
copath-nil_wf, 
copath-cons_wf, 
top_wf, 
sg-legal2_wf, 
coPathAgree_wf, 
equal-wf-base, 
coPathAgree0_lemma, 
sg-change-init_wf, 
win2_wf, 
false_wf, 
coW-equiv_weakening, 
subtype_rel_weakening, 
coW-ext, 
coW-item_wf, 
le_wf, 
set_subtype_base, 
pi1_wf, 
coPath_wf, 
pi2_wf, 
iff_weakening_equal, 
subtype_rel_self, 
true_wf, 
squash_wf, 
equal_wf, 
int_subtype_base, 
subtype_base_sq, 
copath_wf, 
equal-wf-T-base, 
nat_wf, 
copath-length_wf, 
decidable__int_equal, 
sg-init_wf, 
sg-legal1_wf, 
sg-pos_wf, 
set_wf, 
coW-game_wf, 
win2-iff, 
coW-equiv_inversion, 
coW-equiv-implies, 
coWmem_wf, 
iff_wf, 
coW_wf, 
all_wf, 
coW-equiv_wf
Rules used in proof : 
voidEquality, 
isect_memberEquality, 
independent_pairEquality, 
dependent_set_memberEquality, 
dependent_pairEquality, 
dependent_pairFormation, 
hypothesis_subsumption, 
applyLambdaEquality, 
imageMemberEquality, 
imageElimination, 
promote_hyp, 
independent_isectElimination, 
equalityTransitivity, 
functionExtensionality, 
levelHypothesis, 
equalityUniverse, 
voidElimination, 
inrFormation, 
baseClosed, 
intEquality, 
productEquality, 
equalitySymmetry, 
inlFormation, 
unionElimination, 
natural_numberEquality, 
rename, 
setElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
universeEquality, 
functionEquality, 
because_Cache, 
cumulativity, 
instantiate, 
hypothesis, 
applyEquality, 
lambdaEquality, 
sqequalRule, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[A:\mBbbU{}']
    \mforall{}B:A  {}\mrightarrow{}  Type.  \mforall{}w,w':coW(A;a.B[a]).
        (coW-equiv(a.B[a];w;w')  \mLeftarrow{}{}\mRightarrow{}  \mforall{}z:coW(A;a.B[a]).  (coWmem(a.B[a];z;w)  \mLeftarrow{}{}\mRightarrow{}  coWmem(a.B[a];z;w')))
Date html generated:
2018_07_25-PM-01_48_57
Last ObjectModification:
2018_07_11-PM-00_21_34
Theory : co-recursion
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