Celebratio Mathematica

P. Baum: “On the in­dex of equivari­ant el­lipt­ic op­er­at­ors,” pp. 41–​49 in Op­er­at­or al­geb­ras, quant­iz­a­tion, and non­com­mut­at­ive geo­metry: A centen­ni­al cel­eb­ra­tion hon­or­ing John von Neu­mann and Mar­shall H. Stone. Edi­ted by R. Dor­an and R. V. Kadis­on. Con­tem­por­ary Math­em­at­ics 365. Amer­ic­an Math­em­at­ic­al So­ci­ety (Provid­ence, RI), 2004. MR 2106816 Zbl 1081.​46047 incollection