THE EXISTENCE OF LARGE OMEGA(1)-HOMOGENEOUS BUT NOT OMEGA-HOMOGENEOUSPERMUTATION-GROUPS IS CONSISTENT WITH ZFC+GCH

Authors
Citation
S. Shelah et L. Soukup, THE EXISTENCE OF LARGE OMEGA(1)-HOMOGENEOUS BUT NOT OMEGA-HOMOGENEOUSPERMUTATION-GROUPS IS CONSISTENT WITH ZFC+GCH, Journal of the London Mathematical Society, 48, 1993, pp. 193-203
Citations number
5
Categorie Soggetti
Mathematics, General",Mathematics
ISSN journal
00246107
Volume
48
Year of publication
1993
Part
2
Pages
193 - 203
Database
ISI
SICI code
0024-6107(1993)48:<193:TEOLOB>2.0.ZU;2-5
Abstract
Denote by Perm (lambda) the group of all permutations of a cardinal la mbda. A subgroup G of Perm (lambda) is called kappa-homogeneous if and only if for all X, Y epsilon[lambda](k)appa there is a g epsilon G wi th g'' X = Y. We show that if either (i) lozenge(+) holds and we add o mega(1) Cohen reals to the ground model, or (ii) we add 2(o)mega(1) Co hen reals to the ground model, then in the generic extension for each lambda greater than or equal to omega(2) there is an omega(1)-homogene ous subgroup of Perm(lambda) which is not omega-homogeneous.