This is taxing. Ireland is fighting a European Commission ruling that Apple Operations International must pay back taxes to the Irish government. Dublin stands accused of collaborating with the world’s most valuable company in a multibillion-dollar tax avoidance scheme — allegations both deny. The days of the Celtic Tiger enjoying high-paying corporate jobs while offering international giants tax avoidance and an English-speaking workforce may be coming to a close. But the iPad maker and Irish government plan to appeal, making it unlikely that Apple will be cutting a check anytime soon.