Miklos Nemeth, a Harvard-trained economist, was appointed Wednesday to succeed Communist Party leader Karoly Grosz as premier of Hungary. Veteran economic reformer Reszo Nyers, like Nemeth a member of the ruling Communist Party Politburo, was named to the post of minister of state for the economy. The new appointments, to be approved by parliament Thursday, were announced at a news conference in Budapest by Gyoergy Fejti, secretary of the Communist Party's policy-setting Central Committee. Grosz announced last month he intended to resign as premier in order to concentrate on his position as Communist Party chief. Grosz replaced Janos Kadar last May. Nemeth is expected to guide Hungary into a period of austerity.