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: ℕ
, 
uall: ∀[x:A]. B[x]
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
and: P ∧ Q
, 
nat: ℕ
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
int_seg: {i..j-}
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
squash: ↓T
, 
cand: A c∧ B
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
inject: Inj(A;B;f)
, 
lelt: i ≤ j < k
, 
ge: i ≥ j 
, 
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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