Nuprl Lemma : first-iseg
∀[T:Type]. ∀[P:(T List) ⟶ ℙ].
  ((∀L:T List. Dec(P[L]))
  
⇒ (∀L:T List
        (P[L] 
⇒ (∃L':T List. (L' ≤ L ∧ P[L'] ∧ (∀L'':T List. (L'' ≤ L' 
⇒ P[L''] 
⇒ (L'' = L' ∈ (T List)))))))))
Proof
Definitions occuring in Statement : 
iseg: l1 ≤ l2
, 
list: T List
, 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
guard: {T}
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
prop: ℙ
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
nat: ℕ
, 
ge: i ≥ j 
, 
less_than: a < b
, 
squash: ↓T
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
cand: A c∧ B
, 
true: True
, 
uiff: uiff(P;Q)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cons: [a / b]
, 
bfalse: ff
Lemmas referenced : 
int_seg_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_wf, 
int_seg_wf, 
decidable__equal_int, 
subtract_wf, 
int_seg_subtype, 
false_wf, 
decidable__le, 
intformnot_wf, 
itermSubtract_wf, 
intformeq_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
int_formula_prop_eq_lemma, 
le_wf, 
length_wf, 
non_neg_length, 
nat_properties, 
decidable__lt, 
lelt_wf, 
less_than_wf, 
decidable__assert, 
null_wf3, 
subtype_rel_list, 
top_wf, 
list_wf, 
all_wf, 
exists_wf, 
iseg_wf, 
equal_wf, 
set_wf, 
primrec-wf2, 
nat_wf, 
itermAdd_wf, 
int_term_value_add_lemma, 
length_wf_nat, 
decidable_wf, 
list-cases, 
null_nil_lemma, 
length_of_nil_lemma, 
nil_wf, 
equal-wf-T-base, 
assert_of_null, 
assert_wf, 
true_wf, 
iseg_nil, 
product_subtype_list, 
null_cons_lemma, 
length_of_cons_lemma, 
last_lemma, 
decidable-exists-iseg, 
iseg_length, 
squash_wf, 
length_append, 
cons_wf, 
last_wf, 
iff_weakening_equal, 
iseg_transitivity, 
iseg_append0, 
iseg_weakening, 
iseg_append_iff, 
append_wf, 
cons_iseg
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
natural_numberEquality, 
because_Cache, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
productElimination, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
unionElimination, 
addLevel, 
applyEquality, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
levelHypothesis, 
hypothesis_subsumption, 
dependent_set_memberEquality, 
cumulativity, 
imageElimination, 
independent_functionElimination, 
functionExtensionality, 
functionEquality, 
universeEquality, 
productEquality, 
addEquality, 
baseClosed, 
allFunctionality, 
impliesFunctionality, 
promote_hyp, 
imageMemberEquality, 
hyp_replacement
Latex:
\mforall{}[T:Type].  \mforall{}[P:(T  List)  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}L:T  List.  Dec(P[L]))
    {}\mRightarrow{}  (\mforall{}L:T  List
                (P[L]
                {}\mRightarrow{}  (\mexists{}L':T  List.  (L'  \mleq{}  L  \mwedge{}  P[L']  \mwedge{}  (\mforall{}L'':T  List.  (L''  \mleq{}  L'  {}\mRightarrow{}  P[L'']  {}\mRightarrow{}  (L''  =  L'))))))))
Date html generated:
2018_05_21-PM-07_21_46
Last ObjectModification:
2017_07_26-PM-05_05_22
Theory : general
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