A reduction relation for which postponement of K-contractions, Conservation and Preservation of Stro

Postponement of K-contractions and the conservation theorem do not hold for ordinary but have been established by de Groote for a mixture of with another reduction relation. In this paper, de Groote's results are generalised for a single reduction relation e which generalises. This then is used to solve an open problem of e : the Preservation of Strong Normalisation 1 .