Nuprl Lemma : fun_exp-fixedpoint

[T:Type]. ∀[f:T ⟶ T]. ∀[x:T].  ∀[n:ℕ]. ((f^n x) x ∈ T) supposing (f x) x ∈ T


Proof




Definitions occuring in Statement :  fun_exp: f^n nat: uimplies: supposing a uall: [x:A]. B[x] apply: a function: x:A ⟶ B[x] universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a nat: implies:  Q false: False ge: i ≥  guard: {T} prop: all: x:A. B[x] top: Top decidable: Dec(P) or: P ∨ Q iff: ⇐⇒ Q and: P ∧ Q not: ¬A rev_implies:  Q uiff: uiff(P;Q) subtract: m subtype_rel: A ⊆B le: A ≤ B less_than': less_than'(a;b) true: True bool: 𝔹 unit: Unit it: btrue: tt ifthenelse: if then else fi  bfalse: ff compose: g
Lemmas referenced :  nat_properties less_than_transitivity1 less_than_irreflexivity ge_wf less_than_wf fun_exp0_lemma decidable__le subtract_wf false_wf not-ge-2 less-iff-le condition-implies-le minus-one-mul zero-add minus-one-mul-top minus-add minus-minus add-associates add-swap add-commutes add_functionality_wrt_le add-zero le-add-cancel nat_wf equal_wf fun_exp_unroll le_weakening2 le_wf eq_int_wf bool_wf equal-wf-base int_subtype_base assert_wf le_weakening bnot_wf not_wf uiff_transitivity eqtt_to_assert assert_of_eq_int iff_transitivity iff_weakening_uiff eqff_to_assert assert_of_bnot and_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality hypothesis setElimination rename intWeakElimination lambdaFormation natural_numberEquality independent_isectElimination independent_functionElimination voidElimination sqequalRule lambdaEquality dependent_functionElimination axiomEquality isect_memberEquality voidEquality unionElimination independent_pairFormation productElimination addEquality applyEquality intEquality minusEquality because_Cache cumulativity functionExtensionality equalityTransitivity equalitySymmetry functionEquality universeEquality dependent_set_memberEquality baseApply closedConclusion baseClosed equalityElimination impliesFunctionality hyp_replacement applyLambdaEquality

Latex:
\mforall{}[T:Type].  \mforall{}[f:T  {}\mrightarrow{}  T].  \mforall{}[x:T].    \mforall{}[n:\mBbbN{}].  ((f\^{}n  x)  =  x)  supposing  (f  x)  =  x



Date html generated: 2017_04_14-AM-07_35_00
Last ObjectModification: 2017_02_27-PM-03_07_54

Theory : fun_1


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