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: uimplies: supposing a uall: [x:A]. B[x] apply: a natural_number: $n int: equal: 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 ≥  sq_stable: SqStable(P) implies:  Q squash: T lelt: i ≤ j < k int_seg: {i..j-} nat: injection: A →⟶ B guard: {T} prop: subtype_rel: A ⊆B cand: c∧ B and: P ∧ Q uimplies: 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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