
theorem Th32:
  for C being FormalContext for CP1,CP2 being strict FormalConcept
  of C holds (B-meet(C)).(CP1,CP2) = (B-meet(C)).(CP2,CP1)
proof
  let C be FormalContext;
  let CP1,CP2 be strict FormalConcept of C;
  (ex O being Subset of the carrier of C, A being Subset of the carrier'
of C st (B-meet(C)).(CP1,CP2) = ConceptStr(#O,A#) & O = (the Extent of CP1) /\
(the Extent of CP2) & A = (ObjectDerivation(C)).(( AttributeDerivation(C)). ((
  the Intent of CP1) \/ (the Intent of CP2))) )& ex O9 being Subset of the
  carrier of C, A9 being Subset of the carrier' of C st (B-meet(C)).(CP2,CP1) =
ConceptStr (#O9,A9#) & O9 = (the Extent of CP2) /\ (the Extent of CP1) & A9 = (
  ObjectDerivation(C)).(( AttributeDerivation(C)). ((the Intent of CP2) \/ (the
  Intent of CP1))) by Def17;
  hence thesis;
end;
