Sept 15 (Reuters) - U.S. stocks opened slightly higher on Wednesday as cooling inflation eased some fears of an early reduction in monetary stimulus, while a slowing economic recovery and uncertainty over higher taxes kept gains in check. The Dow Jones Industrial Average rose 3.4 points, or 0.01%, at the open to 34580.95. The S&P 500 rose 4.4 points, or 0.10%, at the open to 4447.49, while the Nasdaq Composite rose 33.6 points, or 0.22%, to 15071.34 at the opening bell. (Reporting by Ambar Warrick; Editing by Maju Samuel)