Nuprl Lemma : permutation-nil-iff
∀[A:Type]. ∀L:A List. (permutation(A;[];L) ⇐⇒ L = [] ∈ (A List))
Proof
Definitions occuring in Statement : 
permutation: permutation(T;L1;L2), 
nil: [], 
list: T List, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
iff: 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, 
uimplies: b supposing a, 
or: P ∨ Q, 
cons: [a / b], 
top: Top, 
ge: i ≥ j , 
le: A ≤ B, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
false: False, 
not: ¬A
Lemmas referenced : 
permutation_wf, 
nil_wf, 
equal-wf-T-base, 
list_wf, 
permutation-length, 
list-cases, 
product_subtype_list, 
length_of_nil_lemma, 
length_of_cons_lemma, 
non_neg_length, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
int_formula_prop_wf, 
permutation-nil
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
cut, 
hypothesis, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
baseClosed, 
universeEquality, 
independent_isectElimination, 
dependent_functionElimination, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
sqequalRule, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
computeAll, 
hyp_replacement, 
equalitySymmetry, 
Error :applyLambdaEquality
Latex:
\mforall{}[A:Type].  \mforall{}L:A  List.  (permutation(A;[];L)  \mLeftarrow{}{}\mRightarrow{}  L  =  [])
Date html generated:
2016_10_21-AM-10_17_38
Last ObjectModification:
2016_07_12-AM-05_32_48
Theory : list_1
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