Nuprl Lemma : vdf-eq-firstn-implies
∀[A,B:Type]. ∀[C:A ⟶ B ⟶ Type]. ∀[f:very-dep-fun(A;B;a,b.C[a;b])]. ∀[L:(a:A × b:B × C[a;b]) List]. ∀[j:ℕ||L||].
  (vdf-eq(A;f;firstn(j;L)) 
⇒ {∀[i:ℕj]. ((fst(L[i])) = (f firstn(i;L) (fst(snd(L[i])))) ∈ A)})
Proof
Definitions occuring in Statement : 
very-dep-fun: very-dep-fun(A;B;a,b.C[a; b])
, 
vdf-eq: vdf-eq(A;f;L)
, 
firstn: firstn(n;as)
, 
select: L[n]
, 
length: ||as||
, 
list: T List
, 
int_seg: {i..j-}
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
so_apply: x[s1;s2]
, 
pi1: fst(t)
, 
pi2: snd(t)
, 
implies: P 
⇒ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
product: 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
, 
guard: {T}
, 
implies: P 
⇒ Q
, 
so_apply: x[s1;s2]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
less_than: a < b
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
int_iseg: {i...j}
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
prop: ℙ
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
le: A ≤ B
, 
so_lambda: λ2x y.t[x; y]
, 
less_than': less_than'(a;b)
Lemmas referenced : 
vdf-eq-implies2, 
firstn_wf, 
length_firstn, 
subtype_rel_sets_simple, 
lelt_wf, 
length_wf, 
le_wf, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
istype-le, 
istype-less_than, 
int_seg_wf, 
vdf-eq_wf, 
list_wf, 
very-dep-fun_wf, 
istype-universe, 
subtype_rel_list, 
top_wf, 
int_seg_subtype_nat, 
istype-false, 
select-firstn, 
firstn-firstn
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
lambdaFormation_alt, 
productEquality, 
applyEquality, 
setElimination, 
rename, 
productElimination, 
imageElimination, 
independent_functionElimination, 
dependent_set_memberEquality_alt, 
independent_pairFormation, 
intEquality, 
lambdaEquality_alt, 
natural_numberEquality, 
inhabitedIsType, 
independent_isectElimination, 
dependent_functionElimination, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
Error :memTop, 
universeIsType, 
voidElimination, 
productIsType, 
because_Cache, 
functionIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[A,B:Type].  \mforall{}[C:A  {}\mrightarrow{}  B  {}\mrightarrow{}  Type].  \mforall{}[f:very-dep-fun(A;B;a,b.C[a;b])].  \mforall{}[L:(a:A  \mtimes{}  b:B  \mtimes{}  C[a;b])  List].
\mforall{}[j:\mBbbN{}||L||].
    (vdf-eq(A;f;firstn(j;L))  {}\mRightarrow{}  \{\mforall{}[i:\mBbbN{}j].  ((fst(L[i]))  =  (f  firstn(i;L)  (fst(snd(L[i])))))\})
Date html generated:
2020_05_19-PM-09_40_55
Last ObjectModification:
2020_03_06-PM-03_48_10
Theory : co-recursion-2
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