Nuprl Lemma : copath-tl_wf
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])]. ∀[p:copath(a.B[a];w)].
  copath-tl(p) ∈ copath(a.B[a];coW-item(w;copath-hd(p))) supposing 0 < copath-length(p)
Proof
Definitions occuring in Statement : 
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, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
member: t ∈ T, 
function: x:A ⟶ B[x], 
natural_number: $n, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
copath: copath(a.B[a];w), 
copath-length: copath-length(p), 
pi1: fst(t), 
coPath: coPath(a.B[a];w;n), 
prop: ℙ, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
nat: ℕ, 
false: False, 
guard: {T}, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
copath-tl: copath-tl(x), 
copath-hd: copath-hd(p), 
pi2: snd(t), 
decidable: Dec(P), 
or: P ∨ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
not: ¬A, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
subtract: n - m, 
le: A ≤ B, 
less_than': less_than'(a;b), 
true: True, 
sq_type: SQType(T), 
ifthenelse: if b then t else f fi , 
btrue: tt, 
bfalse: ff
Lemmas referenced : 
less_than_wf, 
copath-length_wf, 
nat_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, 
subtract_wf, 
decidable__le, 
false_wf, 
not-le-2, 
less-iff-le, 
condition-implies-le, 
minus-one-mul, 
zero-add, 
minus-one-mul-top, 
minus-add, 
minus-minus, 
add-associates, 
add-swap, 
add-commutes, 
add_functionality_wrt_le, 
add-zero, 
le-add-cancel, 
le_wf, 
coPath_wf, 
coW-item_wf, 
bool_cases, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
eqtt_to_assert, 
assert_of_eq_int, 
eqff_to_assert, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
productElimination, 
thin, 
sqequalRule, 
hypothesis, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
extract_by_obid, 
isectElimination, 
natural_numberEquality, 
hypothesisEquality, 
lambdaEquality, 
applyEquality, 
setElimination, 
rename, 
isect_memberEquality, 
because_Cache, 
instantiate, 
cumulativity, 
functionEquality, 
universeEquality, 
independent_isectElimination, 
dependent_functionElimination, 
independent_functionElimination, 
voidElimination, 
intEquality, 
baseClosed, 
dependent_pairEquality, 
dependent_set_memberEquality, 
unionElimination, 
independent_pairFormation, 
lambdaFormation, 
addEquality, 
minusEquality, 
impliesFunctionality
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].  \mforall{}[p:copath(a.B[a];w)].
    copath-tl(p)  \mmember{}  copath(a.B[a];coW-item(w;copath-hd(p)))  supposing  0  <  copath-length(p)
Date html generated:
2018_07_25-PM-01_39_49
Last ObjectModification:
2018_06_01-AM-10_10_46
Theory : co-recursion
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