Nuprl Lemma : fix_wf1

[F:{F:ℕ ⟶ Type| Top ⊆(F 0)} ]. ∀[G:⋂n:ℕ((F n) ⟶ (F (n 1)))].  (fix(G) ∈ ⋂n:ℕ(F n))


Proof




Definitions occuring in Statement :  nat: subtype_rel: A ⊆B uall: [x:A]. B[x] top: Top member: t ∈ T set: {x:A| B[x]}  apply: a fix: fix(F) isect: x:A. B[x] function: x:A ⟶ B[x] add: m natural_number: $n universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T nat: implies:  Q false: False ge: i ≥  uimplies: supposing a satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] not: ¬A all: x:A. B[x] top: Top and: P ∧ Q prop: decidable: Dec(P) or: P ∨ Q subtype_rel: A ⊆B le: A ≤ B less_than': less_than'(a;b)
Lemmas referenced :  subtype_rel_self subtract-add-cancel false_wf top_wf subtype_rel_wf le_wf int_term_value_add_lemma itermAdd_wf nat_wf int_term_value_subtract_lemma int_formula_prop_not_lemma itermSubtract_wf intformnot_wf subtract_wf decidable__le 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 isect_memberEquality setElimination thin rename lemma_by_obid sqequalHypSubstitution isectElimination hypothesisEquality hypothesis intWeakElimination lambdaFormation natural_numberEquality independent_isectElimination dependent_pairFormation lambdaEquality int_eqEquality intEquality dependent_functionElimination voidElimination voidEquality sqequalRule independent_pairFormation computeAll independent_functionElimination axiomEquality equalityTransitivity equalitySymmetry unionElimination isectEquality functionEquality applyEquality because_Cache dependent_set_memberEquality addEquality setEquality cumulativity universeEquality

Latex:
\mforall{}[F:\{F:\mBbbN{}  {}\mrightarrow{}  Type|  Top  \msubseteq{}r  (F  0)\}  ].  \mforall{}[G:\mcap{}n:\mBbbN{}.  ((F  n)  {}\mrightarrow{}  (F  (n  +  1)))].    (fix(G)  \mmember{}  \mcap{}n:\mBbbN{}.  (F  n))



Date html generated: 2016_05_15-PM-04_12_51
Last ObjectModification: 2016_01_16-AM-11_07_00

Theory : general


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