Nuprl Lemma : l_before-filter
∀[T:Type]
  ∀l:T List. ∀P:{x:T| (x ∈ l)}  ⟶ 𝔹. ∀x,y:T.  (x before y ∈ filter(P;l) 
⇐⇒ x before y ∈ l ∧ (↑(P x)) ∧ (↑(P y)))
Proof
Definitions occuring in Statement : 
l_before: x before y ∈ l
, 
l_member: (x ∈ l)
, 
filter: filter(P;l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
l_before: x before y ∈ l
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
rev_implies: P 
⇐ Q
, 
or: P ∨ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
cand: A c∧ B
Lemmas referenced : 
l_member_wf, 
bool_wf, 
list_wf, 
filter_wf2, 
subtype_rel_list, 
member_sublist, 
cons_wf, 
nil_wf, 
member_filter_2, 
cons_member, 
assert_witness, 
equal_wf, 
sublist_wf, 
assert_wf, 
sublist_filter_2, 
l_all_cons, 
l_all_single
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
hypothesisEquality, 
functionEquality, 
setEquality, 
cumulativity, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
universeEquality, 
functionExtensionality, 
applyEquality, 
independent_isectElimination, 
lambdaEquality, 
setElimination, 
rename, 
because_Cache, 
independent_pairFormation, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
allFunctionality, 
productElimination, 
promote_hyp, 
inlFormation, 
dependent_set_memberEquality, 
inrFormation, 
productEquality, 
hyp_replacement, 
applyLambdaEquality
Latex:
\mforall{}[T:Type]
    \mforall{}l:T  List.  \mforall{}P:\{x:T|  (x  \mmember{}  l)\}    {}\mrightarrow{}  \mBbbB{}.  \mforall{}x,y:T.
        (x  before  y  \mmember{}  filter(P;l)  \mLeftarrow{}{}\mRightarrow{}  x  before  y  \mmember{}  l  \mwedge{}  (\muparrow{}(P  x))  \mwedge{}  (\muparrow{}(P  y)))
Date html generated:
2017_04_17-AM-07_28_19
Last ObjectModification:
2017_02_27-PM-04_06_10
Theory : list_1
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