Nuprl Lemma : not-less-implies-equal
∀x,y:ℤ.  (x = y ∈ ℤ) supposing ((¬x < y) and (¬y < x))
Proof
Definitions occuring in Statement : 
less_than: a < b, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
not: ¬A, 
int: ℤ, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
member: t ∈ T, 
decidable: Dec(P), 
or: P ∨ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
not: ¬A, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
false: False, 
prop: ℙ, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
top: Top, 
le: A ≤ B, 
less_than': less_than'(a;b), 
true: True
Lemmas referenced : 
decidable__int_equal, 
false_wf, 
not-equal-2, 
not-lt-2, 
add_functionality_wrt_le, 
add-swap, 
add-commutes, 
le-add-cancel, 
add-associates, 
not_wf, 
less_than_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
unionElimination, 
independent_pairFormation, 
voidElimination, 
productElimination, 
independent_functionElimination, 
independent_isectElimination, 
isectElimination, 
addEquality, 
natural_numberEquality, 
sqequalRule, 
applyEquality, 
lambdaEquality, 
isect_memberEquality, 
voidEquality, 
intEquality, 
because_Cache, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}x,y:\mBbbZ{}.    (x  =  y)  supposing  ((\mneg{}x  <  y)  and  (\mneg{}y  <  x))
Date html generated:
2016_05_13-PM-03_32_27
Last ObjectModification:
2015_12_26-AM-09_45_20
Theory : arithmetic
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