Hans Kung, a Roman Catholic priest and prominent liberal theologian banned by the Vatican a year ago from teaching in Catholic institutions, will speak at Memorial Church next Wednesday.

According to the Vatican, Kung's views on the Church's leadership and structure, especially the concept of papal infallibility, do not conform to those of the Roman Catholic Church.

"Kung maintains that the whole Catholic Church can be considered unerring, but that an individual pope's infallibility is out of line with the history of the church," Francine Carpman, a professor at the Weston School of Theology, said yesterday. She added that "because Kung's works are polemical he has become on of today's most controversial theologians."

"Kung's latest works, such as 'Why does God Exist?' deal with issues affecting the broad scope of Christianity. He is one of the most important theologians of our time, and for this reason we wanted him to speak at Harvard," Jane Redmount, an official at the Divinity School, said yesterday.