Nuprl Lemma : pcw-path-coPath_wf
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])]. ∀[p:Path].
  ∀[n:ℕ]
    ((pcw-path-coPath(n;p) ∈ copath(a.B[a];w))
    ∧ ((copath-length(pcw-path-coPath(n;p)) = n ∈ ℤ)
      ⇒ (copath-at(w;pcw-path-coPath(n;p)) = (fst(snd((p n)))) ∈ coW(A;a.B[a])))) 
  supposing StepAgree(p 0;⋅;w)
Proof
Definitions occuring in Statement : 
pcw-path-coPath: pcw-path-coPath(n;p), 
copath-length: copath-length(p), 
copath-at: copath-at(w;p), 
copath: copath(a.B[a];w), 
coW: coW(A;a.B[a]), 
pcw-path: Path, 
pcw-step-agree: StepAgree(s;p1;w), 
nat: ℕ, 
it: ⋅, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
pi1: fst(t), 
pi2: snd(t), 
implies: P ⇒ Q, 
and: P ∧ Q, 
unit: Unit, 
member: t ∈ T, 
apply: f a, 
function: x:A ⟶ B[x], 
natural_number: $n, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
coW: coW(A;a.B[a]), 
less_than': less_than'(a;b), 
le: A ≤ B, 
pcw-path: Path, 
so_apply: x[s1;s2;s3], 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2], 
so_lambda: λ2x y.t[x; y], 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
prop: ℙ, 
and: P ∧ Q, 
top: Top, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
not: ¬A, 
ge: i ≥ j , 
false: False, 
implies: P ⇒ Q, 
nat: ℕ, 
member: t ∈ T, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
coPath-at: coPath-at(n;w;p), 
pi1: fst(t), 
pi2: snd(t), 
copath-nil: (), 
spreadn: spread3, 
pcw-step-agree: StepAgree(s;p1;w), 
copath-at: copath-at(w;p), 
pcw-step: pcw-step(P;p.A[p];p,a.B[p; a];p,a,b.C[p; a; b]), 
btrue: tt, 
ifthenelse: if b then t else f fi , 
subtract: n - m, 
eq_int: (i =z j), 
pcw-path-coPath: pcw-path-coPath(n;p), 
guard: {T}, 
or: P ∨ Q, 
decidable: Dec(P), 
let: let, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
uiff: uiff(P;Q), 
bfalse: ff, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
pcw-steprel: StepRel(s1;s2), 
cand: A c∧ B, 
true: True, 
coW-dom: coW-dom(a.B[a];w), 
squash: ↓T, 
ext-eq: A ≡ B, 
sq_type: SQType(T), 
coW-item: coW-item(w;b)
Lemmas referenced : 
istype-universe, 
coW_wf, 
pcw-path_wf, 
istype-le, 
it_wf, 
unit_wf2, 
pcw-step-agree_wf, 
istype-nat, 
subtract-1-ge-0, 
istype-less_than, 
ge_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
istype-void, 
int_formula_prop_and_lemma, 
istype-int, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformand_wf, 
full-omega-unsat, 
nat_properties, 
equal-wf-base, 
and_wf, 
top_wf, 
param-co-W_wf, 
subtype_rel-equal, 
equal_wf, 
equal-wf-T-base, 
pcw-step_wf, 
le_wf, 
false_wf, 
copath-nil_wf, 
copath_length_nil_lemma, 
int_subtype_base, 
set_subtype_base, 
copath-length_wf, 
subtract-add-cancel, 
int_term_value_subtract_lemma, 
int_formula_prop_not_lemma, 
itermSubtract_wf, 
intformnot_wf, 
decidable__le, 
subtract_wf, 
eq_int_wf, 
bool_wf, 
assert_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
bnot_wf, 
not_wf, 
istype-assert, 
pcw-steprel_wf, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
eqff_to_assert, 
assert_of_bnot, 
istype-top, 
copath-extend_wf, 
coW-ext, 
subtype_rel_weakening, 
pi1_wf, 
coW-dom_wf, 
squash_wf, 
true_wf, 
subtype_rel_self, 
iff_weakening_equal, 
copath-at-extend, 
subtype_base_sq, 
unit_subtype_base, 
coW-item_wf
Rules used in proof : 
universeEquality, 
Error :functionIsType, 
Error :dependent_set_memberEquality_alt, 
applyEquality, 
cumulativity, 
instantiate, 
equalitySymmetry, 
equalityTransitivity, 
Error :inhabitedIsType, 
Error :functionIsTypeImplies, 
axiomEquality, 
Error :universeIsType, 
independent_pairFormation, 
sqequalRule, 
voidElimination, 
Error :isect_memberEquality_alt, 
dependent_functionElimination, 
int_eqEquality, 
Error :lambdaEquality_alt, 
Error :dependent_pairFormation_alt, 
independent_functionElimination, 
approximateComputation, 
independent_isectElimination, 
natural_numberEquality, 
Error :lambdaFormation_alt, 
intWeakElimination, 
rename, 
setElimination, 
hypothesis, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
cut, 
introduction, 
Error :isect_memberFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
intEquality, 
applyLambdaEquality, 
voidEquality, 
isect_memberEquality, 
baseClosed, 
productEquality, 
productElimination, 
lambdaFormation, 
dependent_set_memberEquality, 
because_Cache, 
functionExtensionality, 
lambdaEquality, 
independent_pairEquality, 
sqequalBase, 
closedConclusion, 
baseApply, 
Error :equalityIstype, 
unionElimination, 
equalityElimination, 
hyp_replacement, 
promote_hyp, 
hypothesis_subsumption, 
functionEquality, 
imageElimination, 
imageMemberEquality, 
Error :productIsType
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].  \mforall{}[p:Path].
    \mforall{}[n:\mBbbN{}]
        ((pcw-path-coPath(n;p)  \mmember{}  copath(a.B[a];w))
        \mwedge{}  ((copath-length(pcw-path-coPath(n;p))  =  n)
            {}\mRightarrow{}  (copath-at(w;pcw-path-coPath(n;p))  =  (fst(snd((p  n))))))) 
    supposing  StepAgree(p  0;\mcdot{};w)
Date html generated:
2019_06_20-PM-00_57_04
Last ObjectModification:
2019_04_11-AM-09_56_17
Theory : co-recursion-2
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