Section 1129(b)(2)(A)(iii) of the Bankruptcy Code allows a court to find that a chapter 11 “cramdown” plan is “fair and equitable” to an objecting class of secured creditors if the plan provides for the realization by such holders of the “indubitable equivalent” of their claims. Section 1129(b)(2)(A)(ii), through reference to Section 363(k), permits the sale of collateral free and clear of liens if secured creditors are allowed to “credit bid”—that is, to bid the value of their claim in an auction of the collateral.