Nuprl Lemma : arith-example2
∀f:ℤ ⟶ ℤ. ∀a,b:ℤ.
((a = b ∈ ℤ)
⇒ (∀x,y,z:ℤ.
(((f a) ≤ x)
⇒ (x ≤ (f b))
⇒ (((x - 1) ≤ y) ∧ (y ≤ ((f b) + 1)))
⇒ ((((f b) - 1) ≤ z) ∧ (z ≤ (x + 1)))
⇒ (((y - 1) ≤ z) ∧ (z ≤ (y + 1)))
⇒ (((x = y ∈ ℤ) ∨ (x = z ∈ ℤ)) ∨ (y = z ∈ ℤ)))))
Proof
Definitions occuring in Statement :
le: A ≤ B
,
all: ∀x:A. B[x]
,
implies: P
⇒ Q
,
or: P ∨ Q
,
and: P ∧ Q
,
apply: f a
,
function: x:A ⟶ B[x]
,
subtract: n - m
,
add: n + m
,
natural_number: $n
,
int: ℤ
,
equal: s = t ∈ T
Definitions unfolded in proof :
all: ∀x:A. B[x]
,
implies: P
⇒ Q
,
and: P ∧ Q
,
member: t ∈ T
,
prop: ℙ
,
uall: ∀[x:A]. B[x]
,
subtype_rel: A ⊆r B
,
or: P ∨ Q
,
le: A ≤ B
,
uimplies: b supposing a
,
subtract: n - m
,
top: Top
,
uiff: uiff(P;Q)
,
not: ¬A
,
less_than': less_than'(a;b)
,
true: True
,
false: False
,
iff: P
⇐⇒ Q
,
decidable: Dec(P)
,
rev_implies: P
⇐ Q
,
guard: {T}
Lemmas referenced :
le_wf,
subtract_wf,
equal-wf-base,
int_subtype_base,
false_wf,
or_wf,
condition-implies-le,
add-associates,
minus-one-mul,
add-swap,
minus-one-mul-top,
add_functionality_wrt_le,
add-commutes,
le-add-cancel2,
minus-add,
minus-minus,
le-add-cancel,
le-add-cancel3,
and_wf,
equal_wf,
decidable__int_equal,
not-equal-2
Rules used in proof :
sqequalSubstitution,
sqequalTransitivity,
computationStep,
sqequalReflexivity,
lambdaFormation,
sqequalHypSubstitution,
productElimination,
thin,
productEquality,
cut,
introduction,
extract_by_obid,
isectElimination,
hypothesisEquality,
natural_numberEquality,
hypothesis,
addEquality,
applyEquality,
functionExtensionality,
intEquality,
sqequalRule,
functionEquality,
because_Cache,
unionElimination,
independent_isectElimination,
lambdaEquality,
isect_memberEquality,
voidElimination,
voidEquality,
minusEquality,
independent_functionElimination,
equalitySymmetry,
dependent_set_memberEquality,
independent_pairFormation,
applyLambdaEquality,
setElimination,
rename,
equalityTransitivity,
dependent_functionElimination,
inlFormation,
inrFormation,
addLevel,
orFunctionality
Latex:
\mforall{}f:\mBbbZ{} {}\mrightarrow{} \mBbbZ{}. \mforall{}a,b:\mBbbZ{}.
((a = b)
{}\mRightarrow{} (\mforall{}x,y,z:\mBbbZ{}.
(((f a) \mleq{} x)
{}\mRightarrow{} (x \mleq{} (f b))
{}\mRightarrow{} (((x - 1) \mleq{} y) \mwedge{} (y \mleq{} ((f b) + 1)))
{}\mRightarrow{} ((((f b) - 1) \mleq{} z) \mwedge{} (z \mleq{} (x + 1)))
{}\mRightarrow{} (((y - 1) \mleq{} z) \mwedge{} (z \mleq{} (y + 1)))
{}\mRightarrow{} (((x = y) \mvee{} (x = z)) \mvee{} (y = z)))))
Date html generated:
2017_04_14-AM-07_16_31
Last ObjectModification:
2017_02_27-PM-02_51_51
Theory : arithmetic
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