Sindbad~EG File Manager

RRABC
RRCBD
OSABCD
ANBEAFD+COBCF+NCBCA   defn:oppositeside
BEAFD
COBCF
NCBCA
ANBEABH+EEABHB+EEACHC+NEBC  defn:rightangle
BEABH
EEABHB
EEACHC
NEBC
COABH   defn:collinear
NEBH   lemma:betweennotequal
NEHB   lemma:inequalitysymmetric
RRHBC  lemma:collinearright
RRCBH  lemma:8.2
EQBB    cn:equalityreflexive
COBCB    defn:collinear
OSABCH   defn:oppositeside
OSHBCA   lemma:oppositesidesymmetric
NCBCH    defn:oppositeside
BEHBA   axiom:betweennesssymmetry
BEDFA    axiom:betweennesssymmetry
NCCBD    lemma:rightangleNC
NCBCD    lemma:NCorder
SSHDBC  defn:sameside
SSHDCB  lemma:samesidesymmetric 
RABHD    lemma:erectedperpendicularunique
ORBEBDH|EQHD|BEBHD  lemma:ray1
cases BEABD:BEBDH|EQHD|BEBHD
 case 1:BEBDH
  BEABH
  BEHBA  axiom:betweennesssymmetry
  BEHDB  axiom:betweennesssymmetry
  BEDBA  lemma:3.6a
  BEABD  axiom:betweennesssymmetry
 qedcase
 case 2:EQHD
  BEABD  cn:equalitysub
 qedcase
 case 3:BEBHD
  BEABH
  BEABD lemma:3.7b
 qedcase
BEABD cases