More on SOP_1 and SOP_2
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This paper continues math.LO/0009087. We present a rank function for NSOP_1 theories and give an example of a theory which is NSOP_1 but not simple. We also investigate the connection between maximality in the ordering <^* among complete first order theories and the (N)SOP_2 property. We complete the proof started in math.LO/0009087 of the fact that <^*-maximality implies SOP_2 and get weaker results in the other direction. The paper provides a step toward the classification of unstable theories without the strict order property.
[1] Saharon Shelah. Toward Classifying Unstable Theories , 1996, Ann. Pure Appl. Log..
[2] Saharon Shelah. The Universality Spectrum : Consistency for more Classes , 1994 .
[3] Victor Harnik,et al. Review: S. Shelah, Classification Theory and the Number of Nonisomorphic Models , 1982, Journal of Symbolic Logic.
[4] S. Shelah,et al. Annals of Pure and Applied Logic , 1991 .