Nuprl Lemma : permutation-cons
∀[A:Type]
  ∀x:A. ∀L1,L2:A List.
    (permutation(A;[x / L1];L2) 
⇐⇒ ∃as,bs:A List. ((L2 = (as @ [x / bs]) ∈ (A List)) ∧ permutation(A;L1;as @ bs)))
Proof
Definitions occuring in Statement : 
permutation: permutation(T;L1;L2)
, 
append: as @ bs
, 
cons: [a / b]
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
top: Top
, 
so_apply: x[s]
, 
l_contains: A ⊆ B
, 
l_all: (∀x∈L.P[x])
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
guard: {T}
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
select: L[n]
, 
cons: [a / b]
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
cand: A c∧ B
Lemmas referenced : 
permutation_wf, 
cons_wf, 
exists_wf, 
list_wf, 
equal_wf, 
append_wf, 
length_wf, 
length-append, 
permutation_inversion, 
permutation-contains, 
length_of_cons_lemma, 
false_wf, 
add_nat_plus, 
length_wf_nat, 
less_than_wf, 
nat_plus_wf, 
nat_plus_properties, 
decidable__lt, 
add-is-int-iff, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
itermAdd_wf, 
intformeq_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_formula_prop_eq_lemma, 
int_formula_prop_wf, 
lelt_wf, 
l_member_decomp, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
permutation_transitivity, 
permutation-rotate, 
nil_wf, 
permutation_weakening, 
append_functionality_wrt_permutation, 
cons_cancel_wrt_permutation
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
productElimination, 
sqequalRule, 
lambdaEquality, 
productEquality, 
applyLambdaEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
universeEquality, 
dependent_functionElimination, 
independent_functionElimination, 
because_Cache, 
dependent_set_memberEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
setElimination, 
rename, 
unionElimination, 
pointwiseFunctionality, 
promote_hyp, 
baseApply, 
closedConclusion, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
computeAll, 
addEquality, 
hyp_replacement
Latex:
\mforall{}[A:Type]
    \mforall{}x:A.  \mforall{}L1,L2:A  List.
        (permutation(A;[x  /  L1];L2)
        \mLeftarrow{}{}\mRightarrow{}  \mexists{}as,bs:A  List.  ((L2  =  (as  @  [x  /  bs]))  \mwedge{}  permutation(A;L1;as  @  bs)))
Date html generated:
2017_04_17-AM-08_23_42
Last ObjectModification:
2017_02_27-PM-04_45_25
Theory : list_1
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