Nuprl Lemma : funinv-ap-equals

∀[n:ℕ]. ∀[f:ℕn →⟶ ℕn]. ∀[a,b:ℕn].  (inv(f) b) = a ∈ ℤ supposing (f a) = b ∈ ℤ


Proof




Definitions occuring in Statement :  injection: A →⟶ B,  funinv: inv(f),  int_seg: {i..j-},  nat: ℕ,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  apply: f a,  natural_number: $n,  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  top: Top,  false: False,  exists: ∃x:A. B[x],  satisfiable_int_formula: satisfiable_int_formula(fmla),  not: ¬A,  or: P ∨ Q,  decidable: Dec(P),  all: ∀x:A. B[x],  ge: i ≥ j ,  sq_stable: SqStable(P),  implies: P ⇒ Q,  squash: ↓T,  lelt: i ≤ j < k,  int_seg: {i..j-},  nat: ℕ,  injection: A →⟶ B,  guard: {T},  prop: ℙ,  subtype_rel: A ⊆r B,  cand: A c∧ B,  and: P ∧ Q,  uimplies: b supposing a,  member: t ∈ T,  uall: ∀[x:A]. B[x]
Lemmas referenced :  nat_wf,  lelt_wf,  int_formula_prop_less_lemma,  intformless_wf,  decidable__lt,  int_formula_prop_wf,  int_formula_prop_eq_lemma,  int_term_value_var_lemma,  int_term_value_constant_lemma,  int_formula_prop_le_lemma,  int_formula_prop_not_lemma,  int_formula_prop_and_lemma,  intformeq_wf,  itermVar_wf,  itermConstant_wf,  intformle_wf,  intformnot_wf,  intformand_wf,  full-omega-unsat,  decidable__le,  nat_properties,  int_seg_properties,  squash_wf,  sq_stable__equal,  equal_wf,  sq_stable__and,  int_seg_wf,  injection_wf,  int_subtype_base,  equal-wf-base-T,  funinv_wf3,  funinv-property
Rules used in proof :  voidEquality,  voidElimination,  int_eqEquality,  dependent_pairFormation,  approximateComputation,  independent_isectElimination,  unionElimination,  axiomEquality,  dependent_functionElimination,  lambdaFormation,  independent_functionElimination,  isect_memberEquality,  imageElimination,  baseClosed,  imageMemberEquality,  productElimination,  natural_numberEquality,  rename,  setElimination,  lambdaEquality,  applyLambdaEquality,  sqequalRule,  applyEquality,  intEquality,  productEquality,  because_Cache,  independent_pairFormation,  equalitySymmetry,  equalityTransitivity,  dependent_set_memberEquality,  hypothesis,  hypothesisEquality,  thin,  isectElimination,  sqequalHypSubstitution,  extract_by_obid,  cut,  introduction,  isect_memberFormation,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution

Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[f:\mBbbN{}n  \mrightarrow{}{}\mrightarrow{}  \mBbbN{}n].  \mforall{}[a,b:\mBbbN{}n].    (inv(f)  b)  =  a  supposing  (f  a)  =  b



Date html generated: 2018_05_21-PM-08_16_32
Last ObjectModification: 2017_12_15-PM-00_54_32

Theory : general


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