6 februari i^j<)
Prof. P. Nyikos, Auburn, Alabama, over: „The set-theoretic independence
of some old problems in general topology".
9 februari i^y^
Prof. D. E. Morgan, Waterloo, Canada, over: „Measuring the performance
of a computer network".
/ / november ipy8
Prof. B. Mitiagin, Parijs, over: ...