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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