Nuprl Lemma : filter-list-diff
∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L1,L2:T List]. ∀[eq:EqDecider(T)].  (filter(P;L1-L2) ~ filter(P;L1)-filter(P;L2))
Proof
Definitions occuring in Statement : 
list-diff: as-bs, 
filter: filter(P;l), 
list: T List, 
deq: EqDecider(T), 
bool: 𝔹, 
uall: ∀[x:A]. B[x], 
function: x:A ⟶ B[x], 
universe: Type, 
sqequal: s ~ t
Definitions unfolded in proof : 
list-diff: as-bs, 
top: Top, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
prop: ℙ, 
implies: P ⇒ Q, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
band: p ∧b q, 
ifthenelse: if b then t else f fi , 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
bfalse: ff, 
false: False, 
not: ¬A, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
subtype_rel: A ⊆r B, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
cand: A c∧ B
Lemmas referenced : 
filter-sq, 
l_member_wf, 
bnot_wf, 
deq-member_wf, 
bool_wf, 
eqtt_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
eqff_to_assert, 
assert-bnot, 
assert-deq-member, 
filter_wf5, 
subtype_rel_dep_function, 
subtype_rel_self, 
set_wf, 
assert_witness, 
assert_wf, 
not_wf, 
member_filter_2, 
iff_wf, 
band_wf, 
bfalse_wf, 
assert_elim, 
and_wf, 
btrue_neq_bfalse, 
deq_wf, 
list_wf, 
filter-filter, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_band, 
assert_of_bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
lambdaEquality, 
lambdaFormation, 
cumulativity, 
hypothesis, 
setElimination, 
rename, 
unionElimination, 
equalityElimination, 
productElimination, 
independent_isectElimination, 
because_Cache, 
dependent_pairFormation, 
equalityTransitivity, 
equalitySymmetry, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
independent_functionElimination, 
applyEquality, 
functionExtensionality, 
setEquality, 
independent_pairFormation, 
productEquality, 
addLevel, 
impliesFunctionality, 
andLevelFunctionality, 
impliesLevelFunctionality, 
levelHypothesis, 
dependent_set_memberEquality, 
applyLambdaEquality, 
functionEquality, 
universeEquality, 
isect_memberFormation, 
sqequalAxiom
Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L1,L2:T  List].  \mforall{}[eq:EqDecider(T)].
    (filter(P;L1-L2)  \msim{}  filter(P;L1)-filter(P;L2))
Date html generated:
2017_04_17-AM-09_14_58
Last ObjectModification:
2017_02_27-PM-05_20_51
Theory : decidable!equality
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