Nuprl Lemma : req*_functionality

∀[x1,x2,y1,y2:ℝ*].  (x1 = x2 ⇒ y1 = y2 ⇒ (x1 = y1 ⇐⇒ x2 = y2))


Proof




Definitions occuring in Statement :  req*: x = y,  real*: ℝ*,  uall: ∀[x:A]. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  implies: P ⇒ Q,  iff: P ⇐⇒ Q,  and: P ∧ Q,  member: t ∈ T,  prop: ℙ,  rev_implies: P ⇐ Q
Lemmas referenced :  req*_wf,  real*_wf,  req*_transitivity,  req*_inversion
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  independent_pairFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  independent_functionElimination,  because_Cache

Latex:
\mforall{}[x1,x2,y1,y2:\mBbbR{}*].    (x1  =  x2  {}\mRightarrow{}  y1  =  y2  {}\mRightarrow{}  (x1  =  y1  \mLeftarrow{}{}\mRightarrow{}  x2  =  y2))



Date html generated: 2018_05_22-PM-03_14_38
Last ObjectModification: 2017_10_06-PM-02_09_21

Theory : reals_2


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