Nuprl Lemma : even-implies
∀n:ℤ. ((↑isEven(n)) 
⇒ {((↑isOdd(n - 1)) ∧ (¬↑isOdd(n))) ∧ (↑isOdd(n + 1))})
Proof
Definitions occuring in Statement : 
isEven: isEven(n)
, 
isOdd: isOdd(n)
, 
assert: ↑b
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
subtract: n - m
, 
add: n + m
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
member: t ∈ T
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
not: ¬A
, 
top: Top
, 
isEven: isEven(n)
, 
int_nzero: ℤ-o
, 
true: True
, 
nequal: a ≠ b ∈ T 
, 
sq_type: SQType(T)
, 
subtype_rel: A ⊆r B
, 
uiff: uiff(P;Q)
, 
isOdd: isOdd(n)
, 
eq_int: (i =z j)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
Lemmas referenced : 
false_wf, 
nequal_wf, 
true_wf, 
int_subtype_base, 
subtype_base_sq, 
modulus_wf, 
assert_of_eq_int, 
equal_wf, 
int_formula_prop_wf, 
int_term_value_mul_lemma, 
int_term_value_add_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_term_value_subtract_lemma, 
int_formula_prop_eq_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
itermMultiply_wf, 
itermAdd_wf, 
itermConstant_wf, 
itermVar_wf, 
itermSubtract_wf, 
intformeq_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
decidable__equal_int, 
subtract_wf, 
assert-isOdd, 
assert-isEven, 
isEven_wf, 
assert_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
independent_pairFormation, 
cut, 
hypothesis, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
intEquality, 
dependent_functionElimination, 
productElimination, 
independent_functionElimination, 
natural_numberEquality, 
dependent_pairFormation, 
because_Cache, 
unionElimination, 
independent_isectElimination, 
lambdaEquality, 
int_eqEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
computeAll, 
addEquality, 
multiplyEquality, 
dependent_set_memberEquality, 
addLevel, 
instantiate, 
cumulativity, 
equalityTransitivity, 
equalitySymmetry, 
applyEquality
Latex:
\mforall{}n:\mBbbZ{}.  ((\muparrow{}isEven(n))  {}\mRightarrow{}  \{((\muparrow{}isOdd(n  -  1))  \mwedge{}  (\mneg{}\muparrow{}isOdd(n)))  \mwedge{}  (\muparrow{}isOdd(n  +  1))\})
Date html generated:
2016_05_14-PM-04_24_01
Last ObjectModification:
2016_01_14-PM-11_37_55
Theory : num_thy_1
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