MONDAY The fourth Information Security Matrix Forum 2007 begins at 9 a.m. at the King George Palace Hotel in Athens. To tomorrow. Tel. 210.368.0006 or log on to www.securitymatrix.net. WEDNESDAY KPMG hosts the sixth Chief Financial Officers Forum «CFO Forum» at 9 a.m. at the Divani Caravel Hotel. To tomorrow. Tel. 210.606.2386 or log on to www.kpmg.gr. Real Travel SA holds a conference on «Holiday Homes in Greece: Opportunities for Tourism Development and Investments,» at the King George Palace Hotel in Athens. To be addressed by Environment Minister Giorgos Souflias. THURSDAY The first summer vacation fair Summer Holidays Expo 2007 opens at the Helexpo fairground in Thessaloniki and will run through Sunday. The third symposium of the Greek Marketing Academy on «Bridging Science and Marketing Practices for Boosting Competitiveness,» at the Ledra Marriott Hotel. To tomorrow. Hellenic Petroleum will hold its annual general meeting at its headquarters in Aspropyrgos at noon. FRIDAY The European Union of Small and Medium-Sized Enterprises (EUSME) holds a two-day conference in Athens on «The Social and Business Face of Small and Medium-Sized Enterprises in an Enlarged European Union,» at 2 p.m. at the Divani Apollon Palace Hotel in Vouliagmeni. Development Minister Dimitris Sioufas will make the opening address. To tomorrow. An international exhibition on Greek real estate and tourism «Tourism and Property Show 2007,» begins at the Old Airport at Hellenikon and will run through Monday. Tourism Minister Fanni Palli-Petralia will open the exhibition.