Americans do not go in for envy. The gap between rich and poor is bigger than in any other advanced country, but most people are unconcerned. Whereas Europeans fret about the way the economic pie is divided, Americans want to join the rich, not soak them. Eight out of ten, more than anywhere else, believe that though you may start poor, if you work hard, you can make lots of money. It is a central part of the American Dream. The political consensus, therefore, has sought to pursue economic growth rather than the redistribution of income, in keeping with John Kennedy’s adage that "a rising tide lifts all boats." The tide has been rising fast recently. Thanks to a jump in productivity growth after 1995, America’s economy has outpaced other rich countries’ for a decade. Its workers now produce over 30% more each hour they work than ten years ago. In the late 1990s everybody shared in this boom. Though incomes were rising fastest at the top, all workers’ wages far outpaced inflation.

民事行为被确认为无效或被撤销后，涉及到财产问题如何处理？