L. Soukup:
A non-special omega_2-tree with special omega_1-subtrees
Answering a question of F. Tall it is shown that if
ZF is consistent then so is ZFC + GCH + ``there exists a
non-special omega_2-Aronszajn tree having only special
omega_1-subtrees''.
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appeared in Comm. Math. Univ. Carol., 31, vol 3, 124-129.