A top European diplomat has arrived in Iran to present the government with a package of economic and political incentives to persuade Iran to give up its domestic uranium enrichment program. Iran’s top nuclear negotiator vowed Iran would closely study the proposals, which he said contain positive steps as well as some ambiguities. The incentive package was drawn up last week by the five veto-wielding members of the UN Security Council: the United States, Britain, France, Russia and China.