Nuprl Lemma : rleq*_functionality
∀a,b,c,d:ℝ*.  (a = b ⇒ c = d ⇒ (a ≤ c ⇐⇒ b ≤ d))
Proof
Definitions occuring in Statement : 
rleq*: x ≤ y, 
req*: x = y, 
real*: ℝ*, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rleq*: x ≤ y, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
rev_implies: P ⇐ Q, 
guard: {T}, 
uimplies: b supposing a
Lemmas referenced : 
rleq*_wf, 
req*_wf, 
real*_wf, 
rrel*_functionality, 
rleq_wf, 
real_wf, 
req_inversion, 
rleq_transitivity, 
rleq_weakening, 
req_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
lambdaEquality, 
independent_functionElimination, 
sqequalRule, 
independent_isectElimination, 
because_Cache, 
dependent_functionElimination, 
productElimination
Latex:
\mforall{}a,b,c,d:\mBbbR{}*.    (a  =  b  {}\mRightarrow{}  c  =  d  {}\mRightarrow{}  (a  \mleq{}  c  \mLeftarrow{}{}\mRightarrow{}  b  \mleq{}  d))
Date html generated:
2018_05_22-PM-03_20_23
Last ObjectModification:
2017_10_06-PM-06_06_32
Theory : reals_2
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