A dichotomy on Schreier sets
    
    
  
  
  
      
      
      
        
Studia Mathematica, Tome 132 (1999) no. 3, pp. 245-256
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Institute of Mathematics Polish Academy of Sciences
            
              We show that the Schreier sets $S_α(α  ω_1)$ have the following dichotomy property. For every hereditary collection ℱ of finite subsets of ℱ, either there exists infinite $M = (m_i)_{i=1}^∞ ⊆ ℕ$ such that $S_α(M)={{m_i:i ∈ E}: E ∈ S_α} ⊆ ℱ$, or there exist infinite $M = (m_i)_{i=1}^∞, N ⊆ ℕ$ such that $ℱ[N](M) = {{m_i:i ∈ F}:F ∈ ℱ and F ⊂ N } ⊆ S_α$.
            
            
            
          
        
      @article{10_4064_sm_132_3_245_256,
     author = {Robert Judd},
     title = {A dichotomy on {Schreier} sets},
     journal = {Studia Mathematica},
     pages = {245--256},
     publisher = {mathdoc},
     volume = {132},
     number = {3},
     year = {1999},
     doi = {10.4064/sm-132-3-245-256},
     language = {de},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-132-3-245-256/}
}
                      
                      
                    Robert Judd. A dichotomy on Schreier sets. Studia Mathematica, Tome 132 (1999) no. 3, pp. 245-256. doi: 10.4064/sm-132-3-245-256
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