Nuprl Lemma : pcw-path-copathAgree
∀[A:𝕌']. ∀[B:A ⟶ Type].
  ∀w:coW(A;a.B[a]). ∀path:Path.
    (StepAgree(path 0;⋅;w)
    ⇒ (∀i:ℕ
          ((copath-length(pcw-path-coPath(i + 1;path)) = (i + 1) ∈ ℤ)
          ⇒ (copath-length(pcw-path-coPath(i;path)) = i ∈ ℤ)
          ⇒ copathAgree(a.B[a];w;pcw-path-coPath(i;path);pcw-path-coPath(i + 1;path)))))
Proof
Definitions occuring in Statement : 
pcw-path-coPath: pcw-path-coPath(n;p), 
copathAgree: copathAgree(a.B[a];w;x;y), 
copath-length: copath-length(p), 
coW: coW(A;a.B[a]), 
pcw-path: Path, 
pcw-step-agree: StepAgree(s;p1;w), 
nat: ℕ, 
it: ⋅, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
unit: Unit, 
apply: f a, 
function: x:A ⟶ B[x], 
add: n + m, 
natural_number: $n, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
exposed-it: exposed-it, 
eq_int: (i =z j), 
coPath-extend: coPath-extend(n;p;t), 
coPath: coPath(a.B[a];w;n), 
coPathAgree: coPathAgree(a.B[a];n;w;p;q), 
ge: i ≥ j , 
less_than: a < b, 
copath-extend: copath-extend(q;t), 
copathAgree: copathAgree(a.B[a];w;x;y), 
copath: copath(a.B[a];w), 
spreadn: spread3, 
pcw-step: pcw-step(P;p.A[p];p,a.B[p; a];p,a,b.C[p; a; b]), 
let: let, 
guard: {T}, 
bfalse: ff, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
it: ⋅, 
unit: Unit, 
bool: 𝔹, 
pcw-path-coPath: pcw-path-coPath(n;p), 
cand: A c∧ B, 
coW: coW(A;a.B[a]), 
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_apply: x[s], 
so_lambda: λ2x.t[x], 
true: True, 
less_than': less_than'(a;b), 
le: A ≤ B, 
top: Top, 
subtype_rel: A ⊆r B, 
subtract: n - m, 
squash: ↓T, 
sq_stable: SqStable(P), 
uiff: uiff(P;Q), 
prop: ℙ, 
false: False, 
rev_implies: P ⇐ Q, 
not: ¬A, 
iff: P ⇐⇒ Q, 
or: P ∨ Q, 
decidable: Dec(P), 
nat: ℕ, 
and: P ∧ Q, 
uimplies: b supposing a, 
member: t ∈ T, 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
coW-dom_wf, 
coW-item_wf, 
coPath_wf, 
le_weakening, 
int_subtype_base, 
minus-minus, 
less-iff-le, 
not-ge-2, 
subtract_wf, 
true_wf, 
less_than_wf, 
ge_wf, 
less_than_irreflexivity, 
less_than_transitivity1, 
nat_properties, 
zero-mul, 
add-mul-special, 
not-lt-2, 
decidable__lt, 
equal-wf-base, 
member_wf, 
squash_wf, 
top_wf, 
copath_wf, 
copath-nil-Agree, 
pcw-step_wf, 
add-subtract-cancel, 
le_antisymmetry_iff, 
assert_of_bnot, 
eqff_to_assert, 
iff_weakening_uiff, 
iff_transitivity, 
assert_of_eq_int, 
eqtt_to_assert, 
uiff_transitivity, 
not_wf, 
bnot_wf, 
assert_wf, 
equal-wf-T-base, 
bool_wf, 
eq_int_wf, 
copath-length_wf, 
equal_wf, 
sq_stable__copathAgree, 
coW_wf, 
pcw-path_wf, 
it_wf, 
unit_wf2, 
pcw-step-agree_wf, 
nat_wf, 
le_wf, 
le-add-cancel, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-swap, 
add-associates, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
minus-add, 
condition-implies-le, 
sq_stable__le, 
not-le-2, 
false_wf, 
decidable__le, 
pcw-path-coPath_wf
Rules used in proof : 
closedConclusion, 
baseApply, 
functionExtensionality, 
independent_pairEquality, 
axiomEquality, 
intWeakElimination, 
multiplyEquality, 
productEquality, 
sqequalAxiom, 
lessCases, 
impliesFunctionality, 
equalityElimination, 
equalitySymmetry, 
equalityTransitivity, 
universeEquality, 
functionEquality, 
cumulativity, 
instantiate, 
minusEquality, 
because_Cache, 
intEquality, 
voidEquality, 
isect_memberEquality, 
lambdaEquality, 
applyEquality, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
sqequalRule, 
independent_functionElimination, 
voidElimination, 
independent_pairFormation, 
unionElimination, 
dependent_functionElimination, 
natural_numberEquality, 
rename, 
setElimination, 
addEquality, 
dependent_set_memberEquality, 
productElimination, 
hypothesis, 
independent_isectElimination, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].
    \mforall{}w:coW(A;a.B[a]).  \mforall{}path:Path.
        (StepAgree(path  0;\mcdot{};w)
        {}\mRightarrow{}  (\mforall{}i:\mBbbN{}
                    ((copath-length(pcw-path-coPath(i  +  1;path))  =  (i  +  1))
                    {}\mRightarrow{}  (copath-length(pcw-path-coPath(i;path))  =  i)
                    {}\mRightarrow{}  copathAgree(a.B[a];w;pcw-path-coPath(i;path);pcw-path-coPath(i  +  1;path)))))
Date html generated:
2018_07_25-PM-01_41_46
Last ObjectModification:
2018_07_23-PM-00_54_25
Theory : co-recursion
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