Wall Street welcomed a cease-fire between Israel and Lebanon Monday, sending stocks sharply higher as oil prices tumbled. The Dow Jones industrial average jumped 107 points by midday. With no economic data and little corporate news of note, investors saw the cease-fire as a buying opportunity after last week's losses. Crude futures fell as traders saw less risk of a supply disruption in the Middle East after the United Nations-mandated cease-fire took effect. A barrel of light crude was quoted at $73.25, down $1.10, on the New York Mercantile Exchange.