基于互模拟的三支粒化近似

本文提出了基于互模拟的三支粒化近似,揭示了基于潜在关系的三支粒化近似和基于互似(由潜在关系诱导的最大的互模拟)的三支粒化近似之间的关系.     

Products of coalgebras

We prove that the category of F-coalgebras is complete, that is products and equalizers exist, provided that the type functor F is bounded or preserves mono sources. This generalizes and simplifies a result of Worrell ([Wor98]). We also describe the relationship between the product and the largest bisimulation between and and find an example of two finite coalgebras whose product is infinite. Received January 11, 2000; accepted in final form October 16, 2000.     

On the axiom of extensionality in the positive set theory

This is a study of the relative interpretability of the axiom of extensionality in the positive set theory. This work has to be considered in the line of works of R. O. Gandy, D. Scott and R. Hinnion who have studied the relative interpretability of the axiom of extensionality in set theories of Zermelo and Zermelo‐Fraenkel.