Nuprl Lemma : isl-prior
∀[T:Type]
  ∀f:ℕ ⟶ (T + Top). ∀n:ℕ.
    let m,x = outl(prior(n;f)) 
    in ((f m) = (inl x) ∈ (T + Top)) ∧ (∀k:{m + 1..n-}. (¬↑isl(f k))) 
    supposing ↑isl(prior(n;f))
Proof
Definitions occuring in Statement : 
prior: prior(n;f)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
outl: outl(x)
, 
assert: ↑b
, 
isl: isl(x)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
and: P ∧ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
spread: spread def, 
inl: inl x
, 
union: left + right
, 
add: n + m
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
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)
, 
outl: outl(x)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
uimplies: b supposing a
, 
true: True
, 
prop: ℙ
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
int_seg: {i..j-}
, 
so_lambda: λ2x.t[x]
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
so_apply: x[s]
, 
bfalse: ff
Lemmas referenced : 
prior-cases, 
prior_wf, 
nat_wf, 
int_seg_wf, 
unit_wf2, 
true_wf, 
equal_wf, 
top_wf, 
int_seg_subtype_nat, 
false_wf, 
all_wf, 
not_wf, 
assert_wf, 
isl_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, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
independent_pairFormation, 
inlEquality, 
because_Cache, 
addEquality, 
lambdaEquality, 
applyLambdaEquality, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
independent_functionElimination, 
functionEquality, 
universeEquality
Latex:
\mforall{}[T:Type]
    \mforall{}f:\mBbbN{}  {}\mrightarrow{}  (T  +  Top).  \mforall{}n:\mBbbN{}.
        let  m,x  =  outl(prior(n;f)) 
        in  ((f  m)  =  (inl  x))  \mwedge{}  (\mforall{}k:\{m  +  1..n\msupminus{}\}.  (\mneg{}\muparrow{}isl(f  k))) 
        supposing  \muparrow{}isl(prior(n;f))
Date html generated:
2017_10_01-AM-09_12_10
Last ObjectModification:
2017_07_26-PM-04_47_56
Theory : general
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