Nuprl Lemma : strict-majority-property
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[L:T List]. ∀[x:T].
  uiff(||L|| < 2 * ||filter(λy.(eq y x);L)||;strict-majority(eq;L) = (inl x) ∈ (T?))
Proof
Definitions occuring in Statement : 
strict-majority: strict-majority(eq;L), 
length: ||as||, 
filter: filter(P;l), 
list: T List, 
deq: EqDecider(T), 
less_than: a < b, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
unit: Unit, 
apply: f a, 
lambda: λx.A[x], 
inl: inl x, 
union: left + right, 
multiply: n * m, 
natural_number: $n, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
prop: ℙ, 
deq: EqDecider(T), 
let: let, 
strict-majority: strict-majority(eq;L), 
uimplies: b supposing a, 
and: P ∧ Q, 
uiff: uiff(P;Q), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
exists: ∃x:A. B[x], 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
le: A ≤ B, 
ge: i ≥ j , 
eqof: eqof(d), 
false: False, 
not: ¬A, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
or: P ∨ Q, 
decidable: Dec(P), 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
pi1: fst(t), 
true: True, 
less_than': less_than'(a;b), 
subtract: n - m, 
sq_stable: SqStable(P), 
subtype_rel: A ⊆r B, 
cand: A c∧ B, 
squash: ↓T, 
less_than: a < b, 
nat_plus: ℕ+, 
nat: ℕ, 
cons: [a / b], 
assert: ↑b, 
bnot: ¬bb, 
guard: {T}, 
sq_type: SQType(T), 
btrue: tt, 
it: ⋅, 
unit: Unit, 
bool: 𝔹, 
exposed-bfalse: exposed-bfalse, 
bfalse: ff, 
ifthenelse: if b then t else f fi , 
pi2: snd(t), 
no_repeats: no_repeats(T;l), 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
top: Top, 
rev_uimplies: rev_uimplies(P;Q), 
l_member: (x ∈ l), 
nequal: a ≠ b ∈ T , 
isl: isl(x), 
outl: outl(x)
Lemmas referenced : 
istype-universe, 
deq_wf, 
list_wf, 
member-less_than, 
strict-majority_wf, 
unit_wf2, 
l_member_wf, 
filter_wf5, 
length_wf, 
istype-less_than, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_and_lemma, 
istype-int, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformand_wf, 
full-omega-unsat, 
non_neg_length, 
length_of_nil_lemma, 
istype-assert, 
safe-assert-deq, 
assert_wf, 
not_wf, 
l_all_iff, 
filter_is_nil, 
decidable__l_member, 
decidable-equal-deq, 
count-repeats_wf, 
pi1_wf, 
nat_plus_wf, 
member-map, 
member-count-repeats1, 
member-count-repeats3, 
le-add-cancel2, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-associates, 
minus-one-mul-top, 
add-swap, 
minus-one-mul, 
minus-add, 
condition-implies-le, 
sq_stable__le, 
not-ge-2, 
istype-false, 
decidable__le, 
int_subtype_base, 
le_wf, 
set_subtype_base, 
multiply-is-int-iff, 
length_wf_nat, 
length_of_cons_lemma, 
product_subtype_list, 
list-cases, 
hd_wf, 
equal_wf, 
nil_wf, 
equal-wf-T-base, 
iff_weakening_uiff, 
assert-bnot, 
bool_subtype_base, 
bool_wf, 
subtype_base_sq, 
bool_cases_sqequal, 
eqff_to_assert, 
equal-wf-base-T, 
assert_of_null, 
eqtt_to_assert, 
null_wf, 
reduce_hd_cons_lemma, 
null_cons_lemma, 
pi2_wf, 
lt_int_wf, 
filter_is_singleton, 
no_repeats-count-repeats1, 
no_repeats-l_member!, 
map-length, 
select-map, 
subtype_rel_list, 
top_wf, 
nat_properties, 
nat_plus_properties, 
intformnot_wf, 
int_formula_prop_not_lemma, 
istype-le, 
select_wf, 
map_wf, 
istype-top, 
iff_weakening_equal, 
map_select, 
istype-void, 
istype-nat, 
int_formula_prop_eq_lemma, 
int_term_value_mul_lemma, 
intformeq_wf, 
itermMultiply_wf, 
satisfiable-full-omega-tt, 
decidable__lt, 
assert_of_lt_int, 
eqof_wf, 
less_than_wf, 
decidable__equal_int, 
sum-count-repeats, 
and_wf, 
squash_wf, 
lelt_wf, 
int_seg_wf, 
int_seg_properties, 
isolate_summand, 
neg_assert_of_eq_int, 
assert_of_eq_int, 
eq_int_wf, 
bnot_wf, 
uiff_transitivity, 
iff_transitivity, 
assert_of_bnot, 
false_wf, 
sum_lower_bound, 
int_term_value_add_lemma, 
itermAdd_wf, 
btrue_neq_bfalse, 
bfalse_wf, 
isl_wf, 
btrue_wf, 
bool_cases, 
outl_wf, 
equal-wf-base, 
subtype_rel_product, 
member_filter, 
cons_member, 
nat_wf
Rules used in proof : 
universeEquality, 
instantiate, 
independent_isectElimination, 
because_Cache, 
isectIsTypeImplies, 
axiomEquality, 
isect_memberEquality_alt, 
independent_pairEquality, 
productElimination, 
inlEquality_alt, 
unionIsType, 
equalityIstype, 
universeIsType, 
inhabitedIsType, 
setIsType, 
rename, 
setElimination, 
applyEquality, 
lambdaEquality_alt, 
natural_numberEquality, 
multiplyEquality, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
independent_pairFormation, 
cut, 
introduction, 
isect_memberFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
Error :memTop, 
int_eqEquality, 
dependent_pairFormation_alt, 
approximateComputation, 
voidElimination, 
applyLambdaEquality, 
productIsType, 
equalityTransitivity, 
dependent_set_memberEquality_alt, 
equalitySymmetry, 
hyp_replacement, 
unionElimination, 
lambdaFormation_alt, 
dependent_functionElimination, 
independent_functionElimination, 
productEquality, 
minusEquality, 
imageMemberEquality, 
addEquality, 
intEquality, 
imageElimination, 
hypothesis_subsumption, 
cumulativity, 
promote_hyp, 
baseClosed, 
unionEquality, 
equalityElimination, 
functionIsTypeImplies, 
functionIsType, 
computeAll, 
voidEquality, 
isect_memberEquality, 
dependent_pairFormation, 
setEquality, 
lambdaEquality, 
lambdaFormation, 
functionEquality, 
dependent_set_memberEquality, 
impliesFunctionality, 
inlEquality, 
inlFormation
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[L:T  List].  \mforall{}[x:T].
    uiff(||L||  <  2  *  ||filter(\mlambda{}y.(eq  y  x);L)||;strict-majority(eq;L)  =  (inl  x))
Date html generated:
2020_05_19-PM-09_52_28
Last ObjectModification:
2019_12_26-AM-11_47_50
Theory : decidable!equality
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