Nuprl Lemma : rel_exp_iff
∀n:ℕ
  ∀[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].
    ∀x,y:T.  (x R^n y ⇐⇒ (∃z:T. (0 < n c∧ ((x R^n - 1 z) ∧ (z R y)))) ∨ ((n = 0 ∈ ℤ) ∧ (x = y ∈ T)))
Proof
Definitions occuring in Statement : 
rel_exp: R^n, 
nat: ℕ, 
less_than: a < b, 
uall: ∀[x:A]. B[x], 
cand: A c∧ B, 
prop: ℙ, 
infix_ap: x f y, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
iff: P ⇐⇒ Q, 
or: P ∨ Q, 
and: P ∧ Q, 
function: x:A ⟶ B[x], 
subtract: n - m, 
natural_number: $n, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
so_lambda: λ2x.t[x], 
nat: ℕ, 
decidable: Dec(P), 
or: P ∨ Q, 
uimplies: b supposing a, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
false: False, 
not: ¬A, 
top: Top, 
and: P ∧ Q, 
cand: A c∧ B, 
subtype_rel: A ⊆r B, 
so_apply: x[s], 
ge: i ≥ j , 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
guard: {T}, 
infix_ap: x f y, 
rel_exp: R^n, 
ifthenelse: if b then t else f fi , 
eq_int: (i =z j), 
btrue: tt, 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
le: A ≤ B, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
uiff: uiff(P;Q), 
bfalse: ff, 
sq_type: SQType(T), 
subtract: n - m
Lemmas referenced : 
uall_wf, 
all_wf, 
iff_wf, 
infix_ap_wf, 
rel_exp_wf, 
decidable__le, 
subtract_wf, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermSubtract_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_subtract_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
le_wf, 
or_wf, 
exists_wf, 
less_than_wf, 
equal-wf-base, 
int_subtype_base, 
equal_wf, 
set_wf, 
primrec-wf2, 
nat_properties, 
equal-wf-T-base, 
nat_wf, 
false_wf, 
eq_int_wf, 
bool_wf, 
assert_wf, 
bnot_wf, 
not_wf, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_eq_int, 
iff_transitivity, 
iff_weakening_uiff, 
eqff_to_assert, 
assert_of_bnot, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
less_than_transitivity1, 
le_weakening, 
less_than_irreflexivity, 
and_wf, 
decidable__equal_int, 
subtype_base_sq, 
bool_cases, 
bool_subtype_base
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
thin, 
rename, 
setElimination, 
instantiate, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
universeEquality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
cumulativity, 
hypothesisEquality, 
because_Cache, 
dependent_set_memberEquality, 
dependent_functionElimination, 
natural_numberEquality, 
hypothesis, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
functionExtensionality, 
applyEquality, 
productEquality, 
baseApply, 
closedConclusion, 
baseClosed, 
isect_memberFormation, 
inrFormation, 
imageElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
equalityElimination, 
independent_functionElimination, 
impliesFunctionality, 
inlFormation, 
addLevel, 
hyp_replacement, 
applyLambdaEquality, 
levelHypothesis
Latex:
\mforall{}n:\mBbbN{}
    \mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
        \mforall{}x,y:T.
            (x  R\^{}n  y  \mLeftarrow{}{}\mRightarrow{}  (\mexists{}z:T.  (0  <  n  c\mwedge{}  ((x  R\^{}n  -  1  z)  \mwedge{}  (z  R  y))))  \mvee{}  ((n  =  0)  \mwedge{}  (x  =  y)))
 Date html generated: 
2017_04_17-AM-09_26_24
 Last ObjectModification: 
2017_02_27-PM-05_28_16
Theory : relations2
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