Nuprl Lemma : final-iterate_wf
∀[A:Type]. ∀[f:A ⟶ (A + Top)].  ∀[x:A]. (final-iterate(f;x) ∈ A) supposing SWellFounded(p-graph(A;f) y x)
Proof
Definitions occuring in Statement : 
final-iterate: final-iterate(f;x), 
p-graph: p-graph(A;f), 
strongwellfounded: SWellFounded(R[x; y]), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
top: Top, 
member: t ∈ T, 
apply: f a, 
function: x:A ⟶ B[x], 
union: left + right, 
universe: Type
Definitions unfolded in proof : 
p-graph: p-graph(A;f), 
uall: ∀[x:A]. B[x], 
uimplies: b supposing a, 
member: t ∈ T, 
all: ∀x:A. B[x], 
prop: ℙ, 
so_lambda: λ2x y.t[x; y], 
cand: A c∧ B, 
subtype_rel: A ⊆r B, 
top: Top, 
so_apply: x[s1;s2], 
strongwellfounded: SWellFounded(R[x; y]), 
exists: ∃x:A. B[x], 
nat: ℕ, 
implies: P ⇒ Q, 
false: False, 
ge: i ≥ j , 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
not: ¬A, 
and: P ∧ Q, 
final-iterate: final-iterate(f;x), 
decidable: Dec(P), 
or: P ∨ Q, 
guard: {T}, 
less_than: a < b, 
squash: ↓T, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
bfalse: ff
Lemmas referenced : 
strongwellfounded_wf, 
assert_wf, 
can-apply_wf, 
subtype_rel_union, 
top_wf, 
equal_wf, 
do-apply_wf, 
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, 
le_wf, 
nat_wf, 
decidable__le, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
bool_wf, 
equal-wf-T-base, 
bnot_wf, 
not_wf, 
eqtt_to_assert, 
uiff_transitivity, 
eqff_to_assert, 
assert_of_bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
sqequalHypSubstitution, 
dependent_functionElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
axiomEquality, 
extract_by_obid, 
isectElimination, 
cumulativity, 
lambdaEquality, 
productEquality, 
functionExtensionality, 
applyEquality, 
because_Cache, 
independent_isectElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
functionEquality, 
unionEquality, 
universeEquality, 
productElimination, 
lambdaFormation, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
unionElimination, 
applyLambdaEquality, 
baseClosed, 
imageElimination, 
equalityElimination
Latex:
\mforall{}[A:Type].  \mforall{}[f:A  {}\mrightarrow{}  (A  +  Top)].
    \mforall{}[x:A].  (final-iterate(f;x)  \mmember{}  A)  supposing  SWellFounded(p-graph(A;f)  y  x)
 Date html generated: 
2018_05_21-PM-07_36_42
 Last ObjectModification: 
2017_07_26-PM-05_10_42
Theory : general
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