Oasis, Tuesday, October 4, at the Mercury Cafe, arrives in Colorado intent on substantiating the beliefs of those who feel the band is the next big thing to come out of Manchester, England. The Epic release Definitely Maybe features "Shakermaker," a sardonic twisting of the old Coke jingle "I'd Like to Teach the World to Sing (in Perfect Harmony)," "Supersonic," a tune that epitomizes the act's approach to composition, and "Married With Children," which mellows out without dragging the group down. Just as important are the rock-star-in-the-making lyrics that lead guitarist Noel Gallagher pens for his kid brother Liam, whose delivery sounds like the Beatles meeting Renegade Soundwave. Who cares if Oasis fizzles out faster than fellow overhyped Brit bands? The precious darlings are here now, and that's all that matters.