Tax credit for alternate minimum tax: excess AMT over regular tax may be carried forward and set off. A tax credit is allowed for AMT paid equal to the excess of AMT over regular income-tax; foreign tax credits in excess of regular-tax admissible amounts are ignored. No interest is payable. The credit is carried forward and set off where regular tax exceeds AMT, subject to a limited multi-year carry forward period, and is varied if tax is adjusted by any order. The provision excludes persons who have elected certain optional tax regimes or whose tax is computed under an alternate specified method.