Nuprl Lemma : copathAgree-last
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])]. ∀[p,q:copath(a.B[a];w)].
  (((fst(copath-last(w;q))) = copath-at(w;p) ∈ coW(A;a.B[a]))
     ∧ (copath-at(w;q) = coW-item(copath-at(w;p);snd(copath-last(w;q))) ∈ coW(A;a.B[a]))) supposing 
     ((copath-length(q) = (copath-length(p) + 1) ∈ ℤ) and 
     copathAgree(a.B[a];w;p;q))
Proof
Definitions occuring in Statement : 
copathAgree: copathAgree(a.B[a];w;x;y), 
copath-last: copath-last(w;p), 
copath-length: copath-length(p), 
copath-at: copath-at(w;p), 
copath: copath(a.B[a];w), 
coW-item: coW-item(w;b), 
coW: coW(A;a.B[a]), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
pi1: fst(t), 
pi2: snd(t), 
and: P ∧ Q, 
function: x:A ⟶ B[x], 
add: n + m, 
natural_number: $n, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
coPathAgree: coPathAgree(a.B[a];n;w;p;q), 
rev_uimplies: rev_uimplies(P;Q), 
copath-tl: copath-tl(x), 
pi2: snd(t), 
copath-hd: copath-hd(p), 
eq_int: (i =z j), 
it: ⋅, 
unit: Unit, 
bool: 𝔹, 
bfalse: ff, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
copath-last: copath-last(w;p), 
coPath-at: coPath-at(n;w;p), 
copath-at: copath-at(w;p), 
coPath: coPath(a.B[a];w;n), 
less_than: a < b, 
pi1: fst(t), 
copath-length: copath-length(p), 
copathAgree: copathAgree(a.B[a];w;x;y), 
copath: copath(a.B[a];w), 
sq_type: SQType(T), 
squash: ↓T, 
sq_stable: SqStable(P), 
exists: ∃x:A. B[x], 
true: True, 
less_than': less_than'(a;b), 
le: A ≤ B, 
top: Top, 
subtract: n - m, 
uiff: uiff(P;Q), 
rev_implies: P ⇐ Q, 
not: ¬A, 
iff: P ⇐⇒ Q, 
or: P ∨ Q, 
decidable: Dec(P), 
guard: {T}, 
ge: i ≥ j , 
false: False, 
implies: P ⇒ Q, 
nat: ℕ, 
prop: ℙ, 
subtype_rel: A ⊆r B, 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
all: ∀x:A. B[x], 
cand: A c∧ B, 
and: P ∧ Q, 
uimplies: b supposing a, 
member: t ∈ T, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
coPathAgree_wf, 
and_wf, 
coPath_wf, 
or_wf, 
not-le-2, 
coPath_subtype, 
coPath-at_wf, 
minus-zero, 
le-add-cancel2, 
not-equal-2, 
decidable__int_equal, 
uiff_transitivity, 
assert_of_bnot, 
iff_weakening_uiff, 
iff_transitivity, 
eqff_to_assert, 
assert_of_eq_int, 
eqtt_to_assert, 
bool_subtype_base, 
bool_cases, 
add-subtract-cancel, 
bool_wf, 
equal-wf-T-base, 
not_wf, 
bnot_wf, 
assert_wf, 
le_antisymmetry_iff, 
eq_int_wf, 
sq_stable__equal, 
sq_stable__and, 
add-is-int-iff, 
equal-wf-base, 
member_wf, 
top_wf, 
iff_weakening_equal, 
subtype_rel_self, 
true_wf, 
squash_wf, 
subtype_rel-equal, 
pi2_wf, 
coW-item_wf, 
le-add-cancel-alt, 
not-lt-2, 
decidable__lt, 
subtype_base_sq, 
one-mul, 
zero-mul, 
mul-distributes-right, 
two-mul, 
add-mul-special, 
copath-at_wf, 
pi1_wf, 
coW-dom_wf, 
int_subtype_base, 
set_subtype_base, 
copath-last_wf, 
sq_stable__le, 
le_weakening, 
le_transitivity, 
le-add-cancel, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-swap, 
add-associates, 
minus-minus, 
minus-add, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
condition-implies-le, 
less-iff-le, 
not-ge-2, 
false_wf, 
subtract_wf, 
decidable__le, 
le_wf, 
less_than_wf, 
ge_wf, 
less_than_irreflexivity, 
less_than_transitivity1, 
nat_properties, 
coW_wf, 
copath_wf, 
copathAgree_wf, 
nat_wf, 
equal_wf, 
le_reflexive, 
copath-length_wf
Rules used in proof : 
hyp_replacement, 
applyLambdaEquality, 
dependent_pairEquality, 
orFunctionality, 
addLevel, 
inrFormation, 
inlFormation, 
dependent_set_memberEquality, 
equalityElimination, 
impliesFunctionality, 
closedConclusion, 
baseApply, 
sqequalAxiom, 
lessCases, 
levelHypothesis, 
equalityUniverse, 
multiplyEquality, 
productEquality, 
promote_hyp, 
sqequalIntensionalEquality, 
functionExtensionality, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
dependent_pairFormation, 
minusEquality, 
voidEquality, 
unionElimination, 
voidElimination, 
independent_functionElimination, 
intWeakElimination, 
lambdaFormation, 
universeEquality, 
functionEquality, 
cumulativity, 
instantiate, 
equalitySymmetry, 
equalityTransitivity, 
isect_memberEquality, 
natural_numberEquality, 
addEquality, 
rename, 
setElimination, 
intEquality, 
axiomEquality, 
independent_pairEquality, 
independent_pairFormation, 
productElimination, 
because_Cache, 
independent_isectElimination, 
hypothesis, 
applyEquality, 
lambdaEquality, 
sqequalRule, 
hypothesisEquality, 
isectElimination, 
extract_by_obid, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
introduction, 
cut, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].  \mforall{}[p,q:copath(a.B[a];w)].
    (((fst(copath-last(w;q)))  =  copath-at(w;p))
          \mwedge{}  (copath-at(w;q)  =  coW-item(copath-at(w;p);snd(copath-last(w;q)))))  supposing 
          ((copath-length(q)  =  (copath-length(p)  +  1))  and 
          copathAgree(a.B[a];w;p;q))
Date html generated:
2018_07_25-PM-01_41_25
Last ObjectModification:
2018_07_24-AM-11_49_57
Theory : co-recursion
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