A 7,000-square-foot duplex at the Pierre Hotel is on the market for $50 million, despite the attempts of the heir to the property to stop the sale. Lionel Pincus, the founder of private equity firm Warburg Pincus, owns the 14-room home that takes up the 30th floor and half of the 31st floor at the hotel. Since he was declared mentally incompetent in 2006 his sons Henry and Matthew have become his guardians. Pincus’ wife, Princess Firyal of Jordan, would receive the apartment in the event of Pincus’ death, according to his will, and sued to halt Henry and Matthew’s decision to sell the unit. A judge in Manhattan’s Surrogate Court overturned the princess’s suit in August. Meanwhile, a $70 million penthouse at the Pierre has been on the market since 2005.