BIB-VERSION:: CS-TR-v2.0
          ID:: STAN//CS-TR-93-1499
       ENTRY:: January 27, 1994
ORGANIZATION:: Stanford University, Department of Computer Science
       TITLE:: The Sandwich Theorem
        TYPE:: Technical Report
      AUTHOR:: Knuth, Donald E.
       PAGES:: 50
    ABSTRACT:: This report contains expository notes about a function
               vartheta(G) that is popularly known as the Lovasz number of a
               graph G. There are many ways to define vartheta(G), and the
               surprising variety of different characterizations indicates
               in itself that vartheta(G) should be interesting. But the
               most interesting property of vartheta(G) is probably the fact
               that it can be computed efficiently, although it lies
               "sandwiched" between other classic graph numbers whose
               computation is NP-hard. I have tried to make these notes
               self-contained so that they might serve as an elementary
               introduction to the growing literature on Lovasz's
               fascinating function.
       NOTES:: [Adminitrivia V2/ACK19940321 Added the ORGANIZATION and
               TYPE information]
               [Adminitrivia V1/Prg/19940127]
         END:: STAN//CS-TR-93-1499