Nuprl Lemma : mem_iff_mem_f
∀s:DSet. ∀a:|s|. ∀bs:|s| List.  (↑(a ∈b bs) ⇐⇒ mem_f(|s|;a;bs))
Proof
Definitions occuring in Statement : 
mem: a ∈b as, 
mem_f: mem_f(T;a;bs), 
list: T List, 
assert: ↑b, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
dset: DSet, 
set_car: |p|
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
dset: DSet, 
so_apply: x[s], 
implies: P ⇒ Q, 
top: Top, 
mem_f: mem_f(T;a;bs), 
ycomb: Y, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2;s3], 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
false: False, 
rev_implies: P ⇐ Q, 
prop: ℙ, 
or: P ∨ Q, 
infix_ap: x f y
Lemmas referenced : 
list_induction, 
iff_wf, 
assert_wf, 
mem_wf, 
mem_f_wf, 
set_car_wf, 
mem_nil_lemma, 
istype-void, 
list_ind_nil_lemma, 
mem_cons_lemma, 
list_ind_cons_lemma, 
list_wf, 
dset_wf, 
bor_wf, 
set_eq_wf, 
or_wf, 
equal_wf, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bor, 
assert_of_dset_eq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
because_Cache, 
sqequalRule, 
lambdaEquality_alt, 
dependent_functionElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
universeIsType, 
independent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
productIsType, 
functionIsType, 
inhabitedIsType, 
productElimination, 
unionIsType, 
equalityIsType1, 
unionElimination, 
inlFormation_alt, 
inrFormation_alt, 
promote_hyp, 
applyEquality
Latex:
\mforall{}s:DSet.  \mforall{}a:|s|.  \mforall{}bs:|s|  List.    (\muparrow{}(a  \mmember{}\msubb{}  bs)  \mLeftarrow{}{}\mRightarrow{}  mem\_f(|s|;a;bs))
Date html generated:
2019_10_16-PM-01_03_24
Last ObjectModification:
2018_10_08-AM-11_21_53
Theory : list_2
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