Nuprl Lemma : funinv-property

[n:ℕ]. ∀[f:{f:ℕn ⟶ ℕn| Inj(ℕn;ℕn;f)} ]. ∀[x:ℕn].  (((f (inv(f) x)) x ∈ ℤ) ∧ ((inv(f) (f x)) x ∈ ℕn))


Proof




Definitions occuring in Statement :  funinv: inv(f) inject: Inj(A;B;f) int_seg: {i..j-} nat: uall: [x:A]. B[x] and: P ∧ Q set: {x:A| B[x]}  apply: a function: x:A ⟶ B[x] natural_number: $n int: equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T and: P ∧ Q nat: prop: so_lambda: λ2x.t[x] so_apply: x[s] subtype_rel: A ⊆B int_seg: {i..j-} all: x:A. B[x] uimplies: supposing a squash: T cand: c∧ B true: True guard: {T} iff: ⇐⇒ Q rev_implies:  Q implies:  Q inject: Inj(A;B;f) lelt: i ≤ j < k ge: i ≥  le: A ≤ B decidable: Dec(P) or: P ∨ Q not: ¬A false: False satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] top: Top sq_stable: SqStable(P)
Lemmas referenced :  funinv_wf2 int_seg_wf set_wf inject_wf nat_wf equal_wf squash_wf injection-is-surjection surject_wf true_wf iff_weakening_equal int_seg_properties nat_properties decidable__le lelt_wf satisfiable-full-omega-tt intformand_wf intformle_wf itermConstant_wf itermVar_wf intformnot_wf int_formula_prop_and_lemma int_formula_prop_le_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_not_lemma int_formula_prop_wf decidable__lt intformless_wf int_formula_prop_less_lemma sq_stable__and sq_stable__equal funinv_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality setElimination rename sqequalRule productElimination independent_pairEquality axiomEquality hypothesis natural_numberEquality isect_memberEquality because_Cache functionEquality lambdaEquality functionExtensionality applyEquality intEquality dependent_set_memberEquality setEquality dependent_functionElimination independent_isectElimination applyLambdaEquality imageMemberEquality baseClosed imageElimination equalityTransitivity equalitySymmetry universeEquality independent_functionElimination independent_pairFormation unionElimination voidElimination dependent_pairFormation int_eqEquality voidEquality computeAll lambdaFormation

Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[f:\{f:\mBbbN{}n  {}\mrightarrow{}  \mBbbN{}n|  Inj(\mBbbN{}n;\mBbbN{}n;f)\}  ].  \mforall{}[x:\mBbbN{}n].    (((f  (inv(f)  x))  =  x)  \mwedge{}  ((inv(f)  (f  x))  =  x))



Date html generated: 2017_04_14-AM-09_19_17
Last ObjectModification: 2017_02_27-PM-03_55_22

Theory : int_2


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