Nuprl Lemma : l_tricotomy
∀[T:Type]. ∀x,y:T. ∀L:T List.  ((x ∈ L) 
⇒ (y ∈ L) 
⇒ (((x = y ∈ T) ∨ x before y ∈ L) ∨ y before x ∈ L))
Proof
Definitions occuring in Statement : 
l_before: x before y ∈ l
, 
l_member: (x ∈ l)
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
l_before: x before y ∈ l
, 
l_member: (x ∈ l)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
member: t ∈ T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
uimplies: b supposing a
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
so_apply: x[s]
, 
squash: ↓T
, 
sublist: L1 ⊆ L2
, 
int_seg: {i..j-}
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
uiff: uiff(P;Q)
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
increasing: increasing(f;k)
, 
subtract: n - m
, 
nequal: a ≠ b ∈ T 
, 
less_than': less_than'(a;b)
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
select: L[n]
, 
cons: [a / b]
, 
true: True
Lemmas referenced : 
exists_wf, 
nat_wf, 
less_than_wf, 
length_wf, 
equal_wf, 
select_wf, 
nat_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
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, 
list_wf, 
decidable__lt, 
sublist_wf, 
cons_wf, 
nil_wf, 
decidable__equal_int, 
squash_wf, 
le_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
intformless_wf, 
int_formula_prop_less_lemma, 
or_wf, 
length_of_cons_lemma, 
length_of_nil_lemma, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
lelt_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
int_seg_wf, 
int_seg_properties, 
itermAdd_wf, 
int_term_value_add_lemma, 
increasing_wf, 
false_wf, 
all_wf, 
non_neg_length, 
length_wf_nat, 
equal-wf-T-base, 
assert_wf, 
select-cons-hd, 
bnot_wf, 
not_wf, 
uiff_transitivity, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
int_subtype_base, 
true_wf, 
select_cons_tl, 
length-singleton, 
iff_weakening_equal, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesis, 
lambdaEquality, 
productEquality, 
setElimination, 
rename, 
because_Cache, 
cumulativity, 
hypothesisEquality, 
independent_isectElimination, 
dependent_functionElimination, 
natural_numberEquality, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
universeEquality, 
inlFormation, 
inrFormation, 
applyEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
equalityElimination, 
dependent_set_memberEquality, 
promote_hyp, 
instantiate, 
independent_functionElimination, 
addEquality, 
functionExtensionality, 
applyLambdaEquality, 
impliesFunctionality
Latex:
\mforall{}[T:Type].  \mforall{}x,y:T.  \mforall{}L:T  List.    ((x  \mmember{}  L)  {}\mRightarrow{}  (y  \mmember{}  L)  {}\mRightarrow{}  (((x  =  y)  \mvee{}  x  before  y  \mmember{}  L)  \mvee{}  y  before  x  \mmember{}  L))
Date html generated:
2017_04_14-AM-09_30_01
Last ObjectModification:
2017_02_27-PM-04_02_27
Theory : list_1
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