(decedent utilized tax avoidance plan with intent to avoid state (CA) tax on $660 million in capital gain income; upon death, decedent's estate deducted $62 million on Form 706 for estimated amount of state income tax that would be due if tax avoidance plan failed; IRS disallowed deduction and trial court agreed that deduction should be disallowed because state tax liability (and, hence, deduction) not ascertainable with reasonable certainty as of the date of the decedent's death and decedent had already entered into a settlement with the state as to the amount of capital gain tax liability at $26 million; estate subsequently paid $11 million and then filed refund claim for the $11 million, claiming that $47 million was correct deduction; estate paid $47 million and filed refund claim; deduction not allowed because claim not reasonably certain).