Mayor Vincent Gray and D.C. Council Chairman Kwame Brown are among a contingent of District officials in Las Vegas for a convention sponsored by the International Council of Shopping Centers, and they’re hoping to bring back some big retail investments for the District. A spokesman for Gray declined to specify the companies the mayor will meet with during his visit to Las Vegas citing the sensitive nature of business negotiations, but said they include supermarkets, restaurants and so-called “big box stores.” “You name it, they’re meeting with them,” mayoral spokesman Pedro Ribeiro said. D.C. officials didn’t say how many people were doing the Saturday-through-Tuesday trip. — Alan Blinder