Mexico's Cemex has filed for international arbitration to recover the $290m it paid for a 25 per cent stake in Indonesia's largest cement maker, Semen Gresik, after years of stalled negotiations over a move to majority ownership.  However, the company yesterday indicated it remained interested in the investment and would drop the suit if Semen Gresik's controlling shareholder, the government, acceded to its demands. Cemex bought the 25 per cent stake in 1998 on the understanding it would be allowed to take a 51 per cent stake by 2001.  Wimar Witoelar, a spokesman for Cemex in Jakarta, said while the company had begun the proceedings, it remained interested in a majority stake. "Cemex has always been interested in buying into the Indonesian cement industry. At this point this thing is in the legal process but life is full of possibilities."