Nuprl Lemma : equipollent-iff-list
∀[T:Type]. ∀n:ℕ. (T ~ ℕn 
⇐⇒ ∃L:T List. (no_repeats(T;L) ∧ (||L|| = n ∈ ℤ) ∧ (∀x:T. (x ∈ L))))
Proof
Definitions occuring in Statement : 
equipollent: A ~ B
, 
no_repeats: no_repeats(T;l)
, 
l_member: (x ∈ l)
, 
length: ||as||
, 
list: T List
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
natural_number: $n
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
nat: ℕ
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
biject: Bij(A;B;f)
, 
exists: ∃x:A. B[x]
, 
equipollent: A ~ B
, 
top: Top
, 
cand: A c∧ B
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
guard: {T}
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
le: A ≤ B
, 
lelt: i ≤ j < k
, 
int_seg: {i..j-}
, 
inject: Inj(A;B;f)
, 
surject: Surj(A;B;f)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
ge: i ≥ j 
, 
not: ¬A
, 
false: False
, 
less_than': less_than'(a;b)
, 
l_member: (x ∈ l)
, 
pi1: fst(t)
, 
true: True
, 
squash: ↓T
, 
no_repeats: no_repeats(T;l)
Lemmas referenced : 
nat_wf, 
l_member_wf, 
all_wf, 
length_wf, 
equal_wf, 
no_repeats_wf, 
list_wf, 
exists_wf, 
int_seg_wf, 
equipollent_wf, 
equipollent_inversion, 
length_upto, 
map-length, 
upto_wf, 
map_wf, 
set_wf, 
subtype_rel_dep_function, 
no_repeats_upto, 
no_repeats_map, 
int_subtype_base, 
set_subtype_base, 
subtype_base_sq, 
lelt_wf, 
member_map, 
int_formula_prop_wf, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
itermVar_wf, 
intformless_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
decidable__lt, 
nat_properties, 
int_seg_properties, 
false_wf, 
int_seg_subtype_nat, 
member_upto, 
select_wf, 
less_than_wf, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
itermConstant_wf, 
intformle_wf, 
decidable__le, 
and_wf, 
length_wf_nat, 
non_neg_length, 
biject_wf, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
le_wf, 
iff_weakening_equal, 
true_wf, 
squash_wf, 
decidable__equal_int_seg
Rules used in proof : 
universeEquality, 
because_Cache, 
intEquality, 
productEquality, 
lambdaEquality, 
sqequalRule, 
hypothesis, 
rename, 
setElimination, 
natural_numberEquality, 
hypothesisEquality, 
cumulativity, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
productElimination, 
independent_functionElimination, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
applyEquality, 
functionExtensionality, 
dependent_pairFormation, 
setEquality, 
independent_isectElimination, 
instantiate, 
dependent_set_memberEquality, 
dependent_functionElimination, 
equalitySymmetry, 
computeAll, 
int_eqEquality, 
unionElimination, 
equalityTransitivity, 
applyLambdaEquality, 
hyp_replacement, 
promote_hyp, 
baseClosed, 
imageMemberEquality, 
imageElimination
Latex:
\mforall{}[T:Type].  \mforall{}n:\mBbbN{}.  (T  \msim{}  \mBbbN{}n  \mLeftarrow{}{}\mRightarrow{}  \mexists{}L:T  List.  (no\_repeats(T;L)  \mwedge{}  (||L||  =  n)  \mwedge{}  (\mforall{}x:T.  (x  \mmember{}  L))))
Date html generated:
2018_05_21-PM-00_52_41
Last ObjectModification:
2017_12_07-PM-06_15_42
Theory : equipollence!!cardinality!
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