Nuprl Lemma : copathAgree-tl
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])].
  ∀p,q:copath(a.B[a];w).
    (copathAgree(a.B[a];w;p;q)
    
⇒ 0 < copath-length(p)
    
⇒ 0 < copath-length(q)
    
⇒ copathAgree(a.B[a];coW-item(w;copath-hd(p));copath-tl(p);copath-tl(q)))
Proof
Definitions occuring in Statement : 
copathAgree: copathAgree(a.B[a];w;x;y)
, 
copath-tl: copath-tl(x)
, 
copath-hd: copath-hd(p)
, 
copath-length: copath-length(p)
, 
copath: copath(a.B[a];w)
, 
coW-item: coW-item(w;b)
, 
coW: coW(A;a.B[a])
, 
less_than: a < b
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
copath: copath(a.B[a];w)
, 
copathAgree: copathAgree(a.B[a];w;x;y)
, 
copath-tl: copath-tl(x)
, 
copath-length: copath-length(p)
, 
pi1: fst(t)
, 
member: t ∈ T
, 
nat: ℕ
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
less_than: a < b
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
top: Top
, 
true: True
, 
squash: ↓T
, 
not: ¬A
, 
false: False
, 
prop: ℙ
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
coPathAgree: coPathAgree(a.B[a];n;w;p;q)
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
subtract: n - m
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
coPath: coPath(a.B[a];w;n)
, 
pi2: snd(t)
, 
copath-hd: copath-hd(p)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
decidable__lt, 
top_wf, 
less_than_wf, 
lt_int_wf, 
subtract_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
not-lt-2, 
condition-implies-le, 
add-associates, 
nat_wf, 
minus-add, 
minus-minus, 
minus-one-mul, 
add-swap, 
minus-one-mul-top, 
add-commutes, 
zero-add, 
less-iff-le, 
add_functionality_wrt_le, 
le-add-cancel-alt, 
copath-length_wf, 
copathAgree_wf, 
copath_wf, 
coW_wf, 
eq_int_wf, 
less_than_transitivity1, 
le_weakening, 
less_than_irreflexivity, 
assert_wf, 
bnot_wf, 
not_wf, 
equal-wf-T-base, 
less_than_transitivity2, 
le_weakening2, 
bool_cases, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
sqequalRule, 
cut, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
unionElimination, 
because_Cache, 
lessCases, 
isectElimination, 
sqequalAxiom, 
isect_memberEquality, 
independent_pairFormation, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
independent_functionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
addEquality, 
minusEquality, 
applyEquality, 
lambdaEquality, 
intEquality, 
cumulativity, 
functionEquality, 
universeEquality, 
impliesFunctionality
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].
    \mforall{}p,q:copath(a.B[a];w).
        (copathAgree(a.B[a];w;p;q)
        {}\mRightarrow{}  0  <  copath-length(p)
        {}\mRightarrow{}  0  <  copath-length(q)
        {}\mRightarrow{}  copathAgree(a.B[a];coW-item(w;copath-hd(p));copath-tl(p);copath-tl(q)))
Date html generated:
2018_07_25-PM-01_41_10
Last ObjectModification:
2018_06_01-AM-11_59_21
Theory : co-recursion
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