Celebratio Mathematica

P. F. Baum and E. van Erp: “\( K \)-ho­mo­logy and in­dex the­ory on con­tact man­i­folds,” Acta Math. 213 : 1 (2014), pp. 1–​48. Ded­ic­ated to Sir Mi­chael Atiyah on the oc­ca­sion of his 85th birth­day with ad­mir­a­tion and af­fec­tion. MR 3261009 Zbl 1323.​58017 article

P. F. Baum and E. van Erp: “\( K \)-ho­mo­logy and Fred­holm op­er­at­ors, II: El­lipt­ic op­er­at­ors,” Pure Ap­pl. Math. Q. 12 : 2 (2016), pp. 225–​241. MR 3767216 article

P. F. Baum and E. van Erp: “\( K \)-ho­mo­logy and Fred­holm op­er­at­ors, I: Dir­ac op­er­at­ors,” J. Geom. Phys. 134 (2018), pp. 101–​118. MR 3886929 article