public override WS1SZ3Formula ToWS1SZ3()
 {
     if (WS1SZ3 == null)
     {
         WS1SZ3 = new WS1SZ3Subset(set1, set2);
     }
     return(WS1SZ3);
 }
 public override WS1SZ3Formula ToWS1SZ3()
 {
     if (WS1SZ3 == null)
         WS1SZ3 = new WS1SZ3Subset(set1, set2);
     return WS1SZ3;
 }