Nuprl Lemma : hd-copathAgree
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])]. ∀[x,y:copath(a.B[a];w)].
  (copath-hd(x) = copath-hd(y) ∈ coW-dom(a.B[a];w)) supposing 
     (0 < copath-length(y) and 
     0 < copath-length(x) and 
     copathAgree(a.B[a];w;x;y))
Proof
Definitions occuring in Statement : 
copathAgree: copathAgree(a.B[a];w;x;y)
, 
copath-hd: copath-hd(p)
, 
copath-length: copath-length(p)
, 
copath: copath(a.B[a];w)
, 
coW-dom: coW-dom(a.B[a];w)
, 
coW: coW(A;a.B[a])
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
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)
, 
copathAgree: copathAgree(a.B[a];w;x;y)
, 
all: ∀x:A. B[x]
, 
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
, 
implies: P 
⇒ Q
, 
false: False
, 
prop: ℙ
, 
coPath: coPath(a.B[a];w;n)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
copath-hd: copath-hd(p)
, 
pi2: snd(t)
, 
coPathAgree: coPathAgree(a.B[a];n;w;p;q)
, 
sq_type: SQType(T)
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
bfalse: ff
Lemmas referenced : 
decidable__lt, 
top_wf, 
less_than_wf, 
copath-length_wf, 
copathAgree_wf, 
eq_int_wf, 
less_than_transitivity2, 
le_weakening2, 
less_than_transitivity1, 
le_weakening, 
less_than_irreflexivity, 
assert_wf, 
bnot_wf, 
not_wf, 
equal-wf-T-base, 
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, 
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, 
lambdaFormation, 
imageElimination, 
independent_functionElimination, 
lambdaEquality, 
applyEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
intEquality, 
instantiate, 
cumulativity, 
impliesFunctionality
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].  \mforall{}[x,y:copath(a.B[a];w)].
    (copath-hd(x)  =  copath-hd(y))  supposing 
          (0  <  copath-length(y)  and 
          0  <  copath-length(x)  and 
          copathAgree(a.B[a];w;x;y))
Date html generated:
2018_07_25-PM-01_41_00
Last ObjectModification:
2018_06_01-AM-11_33_40
Theory : co-recursion
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