Nuprl Lemma : fset-size-empty
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[s:fset(T)].  uiff(||s|| ≤ 0;s = {} ∈ fset(T))
Proof
Definitions occuring in Statement : 
fset-size: ||s||
, 
empty-fset: {}
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
le: A ≤ B
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
fset: fset(T)
, 
all: ∀x:A. B[x]
, 
prop: ℙ
, 
quotient: x,y:A//B[x; y]
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
empty-fset: {}
, 
nil: []
, 
it: ⋅
, 
implies: P 
⇒ Q
, 
fset-size: ||s||
, 
or: P ∨ Q
, 
top: Top
, 
cons: [a / b]
, 
deq: EqDecider(T)
, 
ge: i ≥ j 
, 
false: False
, 
le: A ≤ B
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
true: True
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
less_than': less_than'(a;b)
, 
length: ||as||
, 
list_ind: list_ind, 
remove-repeats: remove-repeats(eq;L)
Lemmas referenced : 
list_wf, 
set-equal_wf, 
set-equal-reflex, 
quotient-member-eq, 
set-equal-equiv, 
nil_wf, 
list-cases, 
remove_repeats_nil_lemma, 
istype-void, 
length_of_nil_lemma, 
istype-le, 
product_subtype_list, 
remove_repeats_cons_lemma, 
length_of_cons_lemma, 
non_neg_length, 
filter_wf5, 
remove-repeats_wf, 
l_member_wf, 
bnot_wf, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
itermAdd_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_formula_prop_wf, 
length_wf, 
equal_wf, 
squash_wf, 
true_wf, 
empty-fset_wf, 
subtype_rel_self, 
fset-size_wf, 
istype-false, 
le_wf, 
le_witness_for_triv, 
fset_wf, 
deq_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
sqequalHypSubstitution, 
Error :universeIsType, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
promote_hyp, 
Error :lambdaFormation_alt, 
Error :inhabitedIsType, 
pointwiseFunctionality, 
sqequalRule, 
pertypeElimination, 
productElimination, 
Error :lambdaEquality_alt, 
independent_isectElimination, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
unionElimination, 
Error :isect_memberEquality_alt, 
voidElimination, 
natural_numberEquality, 
because_Cache, 
hypothesis_subsumption, 
rename, 
setElimination, 
applyEquality, 
Error :setIsType, 
approximateComputation, 
Error :dependent_pairFormation_alt, 
int_eqEquality, 
addEquality, 
closedConclusion, 
Error :equalityIstype, 
Error :productIsType, 
sqequalBase, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
instantiate, 
universeEquality, 
hyp_replacement, 
applyLambdaEquality, 
independent_pairEquality, 
axiomEquality, 
Error :isectIsTypeImplies
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[s:fset(T)].    uiff(||s||  \mleq{}  0;s  =  \{\})
Date html generated:
2019_06_20-PM-02_13_48
Last ObjectModification:
2019_06_20-PM-02_07_41
Theory : finite!sets
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