Nuprl Lemma : not-same-parity-implies-even-odd
∀n,m:ℤ.  ((¬↑same-parity(n;m)) ⇒ (((↑isEven(n)) ∧ (↑isOdd(m))) ∨ ((↑isOdd(n)) ∧ (↑isEven(m)))))
Proof
Definitions occuring in Statement : 
same-parity: same-parity(n;m), 
isEven: isEven(n), 
isOdd: isOdd(n), 
assert: ↑b, 
all: ∀x:A. B[x], 
not: ¬A, 
implies: P ⇒ Q, 
or: P ∨ Q, 
and: P ∧ Q, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
same-parity: same-parity(n;m), 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
exists: ∃x:A. B[x], 
prop: ℙ, 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
false: False, 
cand: A c∧ B, 
true: True, 
not: ¬A
Lemmas referenced : 
isEven_wf, 
bool_wf, 
eqtt_to_assert, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
odd-iff-not-even, 
even-iff-not-odd, 
false_wf, 
assert_wf, 
isOdd_wf, 
not_wf, 
same-parity_wf, 
bool_cases, 
assert_of_bnot
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
sqequalHypSubstitution, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
sqequalRule, 
dependent_pairFormation, 
promote_hyp, 
dependent_functionElimination, 
instantiate, 
cumulativity, 
independent_functionElimination, 
because_Cache, 
voidElimination, 
inrFormation, 
independent_pairFormation, 
productEquality, 
intEquality, 
inlFormation, 
natural_numberEquality
Latex:
\mforall{}n,m:\mBbbZ{}.    ((\mneg{}\muparrow{}same-parity(n;m))  {}\mRightarrow{}  (((\muparrow{}isEven(n))  \mwedge{}  (\muparrow{}isOdd(m)))  \mvee{}  ((\muparrow{}isOdd(n))  \mwedge{}  (\muparrow{}isEven(m)))))
Date html generated:
2017_04_17-AM-09_43_40
Last ObjectModification:
2017_02_27-PM-05_38_16
Theory : num_thy_1
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