Nuprl Lemma : vdf-eq-append1
∀A:Type. ∀f:Top. ∀L:(a:Top × b:Top × Top) List. ∀a,b,c:Top.
  (vdf-eq(A;f;L @ [<a, b, c>]) ~ x:vdf-eq(A;f;L) ⋂ a = (f L b) ∈ A)
Proof
Definitions occuring in Statement : 
vdf-eq: vdf-eq(A;f;L)
, 
append: as @ bs
, 
cons: [a / b]
, 
nil: []
, 
list: T List
, 
dep-isect: x:A ⋂ B[x]
, 
top: Top
, 
all: ∀x:A. B[x]
, 
apply: f a
, 
pair: <a, b>
, 
product: x:A × B[x]
, 
universe: Type
, 
sqequal: s ~ t
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
false: False
, 
le: A ≤ B
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
sq_type: SQType(T)
, 
guard: {T}
, 
select: L[n]
, 
cons: [a / b]
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
less_than: a < b
, 
squash: ↓T
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
let: let, 
pi1: fst(t)
, 
pi2: snd(t)
, 
nat: ℕ
, 
less_than': less_than'(a;b)
Lemmas referenced : 
vdf-eq-firstn, 
append_wf, 
top_wf, 
cons_wf, 
nil_wf, 
non_neg_length, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
length-append, 
length_of_cons_lemma, 
length_of_nil_lemma, 
decidable__lt, 
length_wf, 
intformless_wf, 
itermAdd_wf, 
int_formula_prop_less_lemma, 
int_term_value_add_lemma, 
istype-le, 
istype-less_than, 
list_wf, 
istype-top, 
istype-universe, 
select-append, 
subtype_rel_list, 
length_wf_nat, 
subtype_base_sq, 
int_subtype_base, 
decidable__equal_int, 
intformeq_wf, 
itermSubtract_wf, 
int_formula_prop_eq_lemma, 
int_term_value_subtract_lemma, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
firstn-append, 
add_nat_wf, 
istype-void, 
nat_properties, 
add-is-int-iff, 
false_wf, 
le_int_wf, 
assert_of_le_int, 
le_wf, 
firstn_all, 
subtract_wf, 
length-singleton
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
isectElimination, 
productEquality, 
hypothesis, 
dependent_pairEquality_alt, 
inhabitedIsType, 
productIsType, 
dependent_set_memberEquality_alt, 
because_Cache, 
independent_pairFormation, 
unionElimination, 
productElimination, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
Error :memTop, 
sqequalRule, 
universeIsType, 
voidElimination, 
addEquality, 
independent_pairEquality, 
instantiate, 
universeEquality, 
applyEquality, 
closedConclusion, 
cumulativity, 
intEquality, 
equalityTransitivity, 
equalitySymmetry, 
equalityElimination, 
imageElimination, 
equalityIstype, 
promote_hyp, 
applyLambdaEquality, 
setElimination, 
rename, 
pointwiseFunctionality, 
baseApply, 
baseClosed
Latex:
\mforall{}A:Type.  \mforall{}f:Top.  \mforall{}L:(a:Top  \mtimes{}  b:Top  \mtimes{}  Top)  List.  \mforall{}a,b,c:Top.
    (vdf-eq(A;f;L  @  [<a,  b,  c>])  \msim{}  x:vdf-eq(A;f;L)  \mcap{}  a  =  (f  L  b))
Date html generated:
2020_05_19-PM-09_40_41
Last ObjectModification:
2020_03_09-PM-01_39_15
Theory : co-recursion-2
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