Q指数
Q 指數是指數函數的 Q 模擬，定義如下

  
    
      
        
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    {\displaystyle e_{q}(z)=\sum _{n=0}^{\infty}{\frac {z^{n}(1-q)^{n}}{(q;q)_{n}}}=\sum _{n=0}^{\infty} z^{n}{\frac {(1-q)^{n}}{(1-q^{n})(1-q^{n-1})\cdots (1-q)}}}
  其中
  
    
      
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    {\displaystyle (q;q)_{n}=(1-q^{n})(1-q^{n-1})\cdots (1-q)}
  
是 Q 階乘冪

  
    
      
        
          
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    {\displaystyle \left ({\frac {d}{dz}}\right)_{q} e_{q}(z)=e_{q}(z)}
  
  
    
      
        
          
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    {\displaystyle \left ({\frac {d}{dz}}\right)_{q} z^{n}=z^{n-1}{\frac {1-q^{n}}{1-q}}=[n]_{q} z^{n-1}.}