Nuprl Lemma : urec-is-least-fixedpoint
∀[F:Type ⟶ Type]. ∀T:Type. urec(F) ⊆r T supposing F T ≡ T supposing Monotone(T.F T)
Proof
Definitions occuring in Statement : 
urec: urec(F), 
type-monotone: Monotone(T.F[T]), 
ext-eq: A ≡ B, 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
apply: f a, 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
subtype_rel: A ⊆r B, 
urec: urec(F), 
tunion: ⋃x:A.B[x], 
pi2: snd(t), 
nat: ℕ, 
implies: P ⇒ Q, 
false: False, 
ge: i ≥ j , 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
not: ¬A, 
top: Top, 
and: P ∧ Q, 
prop: ℙ, 
decidable: Dec(P), 
or: P ∨ Q, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
squash: ↓T, 
true: True, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
type-monotone: Monotone(T.F[T])
Lemmas referenced : 
fun_exp_wf, 
subtype_rel_weakening, 
subtype_rel_transitivity, 
iff_weakening_equal, 
true_wf, 
squash_wf, 
subtype_rel_wf, 
type-monotone_wf, 
ext-eq_wf, 
urec_wf, 
subtract-add-cancel, 
le_wf, 
fun_exp_apply_add1, 
int_term_value_subtract_lemma, 
int_formula_prop_not_lemma, 
itermSubtract_wf, 
intformnot_wf, 
subtract_wf, 
decidable__le, 
fun_exp0_lemma, 
less_than_wf, 
ge_wf, 
int_formula_prop_wf, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_and_lemma, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
nat_properties
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
lambdaEquality, 
sqequalHypSubstitution, 
imageElimination, 
productElimination, 
thin, 
sqequalRule, 
hypothesisEquality, 
applyEquality, 
lemma_by_obid, 
isectElimination, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
axiomEquality, 
unionElimination, 
instantiate, 
because_Cache, 
dependent_set_memberEquality, 
universeEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}[F:Type  {}\mrightarrow{}  Type].  \mforall{}T:Type.  urec(F)  \msubseteq{}r  T  supposing  F  T  \mequiv{}  T  supposing  Monotone(T.F  T)
Date html generated:
2016_05_15-PM-06_54_53
Last ObjectModification:
2016_01_16-AM-09_48_47
Theory : general
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