Among the private equity players invited this year were Henry R. Kravis of Kohlberg Kravis Roberts -LRB- who did not attend -RRB- ; John A. Canning Jr. , chairman and chief executive of Madison Dearborn Partners ; Stephen Pagliuca of Bain Capital ; Jonathan M. Nelson of Providence Equity Partners ; Timothy C. Collins , chief executive of Ripplewood Holdings ; and William E. Ford , president of General Atlantic .