Nuprl Lemma : filter-filter
∀[P1,P2,L:Top].  (filter(P2;filter(P1;L)) ~ filter(λt.((P1 t) ∧b (P2 t));L))
Proof
Definitions occuring in Statement : 
filter: filter(P;l)
, 
band: p ∧b q
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
apply: f a
, 
lambda: λx.A[x]
, 
sqequal: s ~ t
Definitions unfolded in proof : 
band: p ∧b q
, 
filter: filter(P;l)
, 
reduce: reduce(f;k;as)
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
list_ind: list_ind, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
ifthenelse: if b then t else f fi 
, 
cons: [a / b]
, 
nil: []
, 
it: ⋅
, 
fun_exp: f^n
, 
primrec: primrec(n;b;c)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
nat_plus: ℕ+
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
strict4: strict4(F)
, 
has-value: (a)↓
, 
guard: {T}
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
bfalse: ff
Lemmas referenced : 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
base_wf, 
strictness-apply, 
strictness-callbyvalue, 
bottom-sqle, 
decidable__le, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
fun_exp_unroll_1, 
top_wf, 
lifting-strict-callbyvalue, 
has-value_wf_base, 
is-exception_wf, 
cbv_sqle, 
int_subtype_base, 
has-value-implies-dec-ispair-2, 
lifting-strict-ifthenelse, 
has-value-ifthenelse-type, 
equal_wf, 
has-value-implies-dec-isaxiom-2, 
cbv_bottom_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
sqequalSqle, 
lambdaFormation, 
fixpointLeast, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
axiomSqleEquality, 
unionElimination, 
dependent_set_memberEquality, 
because_Cache, 
sqequalAxiom, 
baseClosed, 
callbyvalueCallbyvalue, 
callbyvalueReduce, 
baseApply, 
closedConclusion, 
callbyvalueExceptionCases, 
inrFormation, 
imageMemberEquality, 
imageElimination, 
exceptionSqequal, 
inlFormation, 
applyEquality, 
equalityTransitivity, 
equalitySymmetry, 
unionEquality, 
sqleReflexivity, 
decideExceptionCases, 
sqleRule, 
divergentSqle
Latex:
\mforall{}[P1,P2,L:Top].    (filter(P2;filter(P1;L))  \msim{}  filter(\mlambda{}t.((P1  t)  \mwedge{}\msubb{}  (P2  t));L))
Date html generated:
2017_04_14-AM-09_27_10
Last ObjectModification:
2017_02_27-PM-04_01_21
Theory : list_1
Home
Index