Alex Hellsten

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Acknowledgements I want to express my sincere gratitude to my supervisor Professor Jouko Väänänen for supporting me during all these years of getting acquainted with the intriguing field of set theory. I am also grateful to all other members of the Helsinki Logic Group for interesting discussions and guidance. Especially I wish to thank Do-cent Tapani(More)
H. R. Olesen, A. Baklanov, J. Bartzis, F. Barmpas, R. Berkowicz, K. Brzozowski, R. Buccolieri, B. Carissimo, A. Costa, S. Di Sabatino, G. Efthimiou, J. Franke, I. Goricsan, A. Hellsten, M. Ketzel, B. Leitl, R. Nuterman, E. Polreich, J. Santiago, R. Tavares NERI, Univ. of Aarhus, Denmark DMI, Denmark; Univ. of West Macedonia, Greece; Aristotle Univ., Greece;(More)
We extract some properties of Mahlo’s operation and show that some other very natural operations share these properties. The weakly compact sets form a similar hierarchy as the stationary sets. The height of this hierarchy is a large cardinal property connected to saturation properties of the weakly compact ideal. 1 2
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