Nuprl Lemma : isl-prior-iff
∀[T:Type]. ∀f:ℕ ⟶ (T + Top). ∀n:ℕ.  (↑isl(prior(n;f)) 
⇐⇒ ∃k:ℕn. (↑isl(f k)))
Proof
Definitions occuring in Statement : 
prior: prior(n;f)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
assert: ↑b
, 
isl: isl(x)
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
union: left + right
, 
natural_number: $n
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
isl: isl(x)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
bfalse: ff
, 
prop: ℙ
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
exists: ∃x:A. B[x]
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
guard: {T}
, 
true: True
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
rev_implies: P 
⇐ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
Lemmas referenced : 
prior-cases, 
prior_wf, 
nat_wf, 
int_seg_wf, 
unit_wf2, 
equal_wf, 
top_wf, 
and_wf, 
isl_wf, 
btrue_wf, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert_wf, 
int_seg_subtype_nat, 
false_wf, 
true_wf, 
exists_wf, 
all_wf, 
not_wf, 
int_seg_properties, 
nat_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermAdd_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_add_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
lambdaFormation, 
dependent_functionElimination, 
cumulativity, 
functionExtensionality, 
applyEquality, 
unionEquality, 
productEquality, 
natural_numberEquality, 
setElimination, 
rename, 
unionElimination, 
sqequalRule, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
functionEquality, 
universeEquality, 
productElimination, 
independent_pairFormation, 
dependent_pairFormation, 
dependent_set_memberEquality, 
applyLambdaEquality, 
instantiate, 
independent_isectElimination, 
lambdaEquality, 
because_Cache, 
inlEquality, 
addEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll
Latex:
\mforall{}[T:Type].  \mforall{}f:\mBbbN{}  {}\mrightarrow{}  (T  +  Top).  \mforall{}n:\mBbbN{}.    (\muparrow{}isl(prior(n;f))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}k:\mBbbN{}n.  (\muparrow{}isl(f  k)))
Date html generated:
2017_10_01-AM-09_12_14
Last ObjectModification:
2017_07_26-PM-04_47_58
Theory : general
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