Nuprl Lemma : rless-cases1
∀x,y:ℝ.  ((x < y) 
⇒ (∀z:ℝ. ((x < z) ∨ (z < y))))
Proof
Definitions occuring in Statement : 
rless: x < y
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
itermConstant: "const"
, 
req_int_terms: t1 ≡ t2
, 
false: False
, 
not: ¬A
, 
top: Top
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
prop: ℙ
, 
guard: {T}
, 
or: P ∨ Q
, 
rsub: x - y
, 
iff: P 
⇐⇒ Q
Lemmas referenced : 
radd-positive-implies, 
rsub_wf, 
rless-implies-rless, 
int-to-real_wf, 
radd_wf, 
real_term_polynomial, 
itermSubtract_wf, 
itermVar_wf, 
itermAdd_wf, 
itermConstant_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_var_lemma, 
real_term_value_add_lemma, 
req-iff-rsub-is-0, 
real_wf, 
rless_wf, 
radd-ac, 
radd-rminus-both, 
radd-preserves-rless, 
rminus_wf, 
rless_functionality, 
radd_comm, 
radd_functionality, 
req_weakening, 
radd-rminus-assoc, 
radd-zero-both
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
independent_functionElimination, 
natural_numberEquality, 
independent_isectElimination, 
sqequalRule, 
computeAll, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
inrFormation, 
lemma_by_obid, 
inlFormation, 
unionElimination, 
promote_hyp
Latex:
\mforall{}x,y:\mBbbR{}.    ((x  <  y)  {}\mRightarrow{}  (\mforall{}z:\mBbbR{}.  ((x  <  z)  \mvee{}  (z  <  y))))
Date html generated:
2017_10_03-AM-08_39_44
Last ObjectModification:
2017_07_28-AM-07_30_53
Theory : reals
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