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We analyze a natural function definable from a scale at a singular cardinal, and use it to obtain some strong negative square-brackets partition relations at successors of singular cardinals. The proof of our main result makes use of club-guessing, and as a corollary we obtain a fairly easy proof of a difficult result of Shelah connecting weak saturation of a certain club-guessing ideal with strong failures of square-brackets partition relations. We then investigate the strength of weak saturation of such ideals and obtain some results on stationary reflection.
Todd Eisworth. "A note on strong negative partition relations." Fundamenta Mathematicae 202.2 (2009): 97-123. <http://eudml.org/doc/282727>.
@article{ToddEisworth2009, abstract = {We analyze a natural function definable from a scale at a singular cardinal, and use it to obtain some strong negative square-brackets partition relations at successors of singular cardinals. The proof of our main result makes use of club-guessing, and as a corollary we obtain a fairly easy proof of a difficult result of Shelah connecting weak saturation of a certain club-guessing ideal with strong failures of square-brackets partition relations. We then investigate the strength of weak saturation of such ideals and obtain some results on stationary reflection.}, author = {Todd Eisworth}, journal = {Fundamenta Mathematicae}, keywords = {successors of singular cardinals; scales; square-brackets partition relations; club guessing}, language = {eng}, number = {2}, pages = {97-123}, title = {A note on strong negative partition relations}, url = {http://eudml.org/doc/282727}, volume = {202}, year = {2009}, }
TY - JOUR AU - Todd Eisworth TI - A note on strong negative partition relations JO - Fundamenta Mathematicae PY - 2009 VL - 202 IS - 2 SP - 97 EP - 123 AB - We analyze a natural function definable from a scale at a singular cardinal, and use it to obtain some strong negative square-brackets partition relations at successors of singular cardinals. The proof of our main result makes use of club-guessing, and as a corollary we obtain a fairly easy proof of a difficult result of Shelah connecting weak saturation of a certain club-guessing ideal with strong failures of square-brackets partition relations. We then investigate the strength of weak saturation of such ideals and obtain some results on stationary reflection. LA - eng KW - successors of singular cardinals; scales; square-brackets partition relations; club guessing UR - http://eudml.org/doc/282727 ER -