Nuprl Lemma : rneq_functionality
∀x1,x2,y1,y2:ℝ.  (x1 ≠ y1 ⇐⇒ x2 ≠ y2) supposing ((y1 = y2) and (x1 = x2))
Proof
Definitions occuring in Statement : 
rneq: x ≠ y, 
req: x = y, 
real: ℝ, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
uimplies: b supposing a, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
rneq: x ≠ y, 
prop: ℙ, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
or: P ∨ Q
Lemmas referenced : 
req_witness, 
req_wf, 
real_wf, 
or_wf, 
rless_wf, 
iff_wf, 
rless_functionality, 
req_weakening
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
cut, 
introduction, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
rename, 
independent_pairFormation, 
because_Cache, 
addLevel, 
productElimination, 
impliesFunctionality, 
orFunctionality, 
dependent_functionElimination, 
independent_isectElimination, 
orLevelFunctionality
Latex:
\mforall{}x1,x2,y1,y2:\mBbbR{}.    (x1  \mneq{}  y1  \mLeftarrow{}{}\mRightarrow{}  x2  \mneq{}  y2)  supposing  ((y1  =  y2)  and  (x1  =  x2))
Date html generated:
2016_05_18-AM-07_10_32
Last ObjectModification:
2015_12_28-AM-00_38_44
Theory : reals
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