Advanced use of SET ANALYSIS

[#1]

Dear all,

I tried to apply the use of the set Analysis with "CLUSTERS" of data.

In specific, I attempted to make the union  of two Clusters (1+2) and the difference (1-2)

I enclose an easy example that do not work propery

More in details, we have 4 items in the first cluster (Giacomo, Gianni, Giovanni, Leopardi) and 3 items in the second (Giacomo, Leopardi, Leopoldo)

Only two of them are in common. The first cluster has 2 elements not included in the second and the second cluster has 1 element not included in the first

The attemps is to create:

1) The INTERSECTION of the 2 clusters, using the operator "*". The example works and the result is 2 items (Giacomo, Leopardi).

    The formula I used is:

     sum( {<Nome=>*<FileDUE.Nome=>} FileDUE.StipendioDUE + StipendioUNO)

2)  The UNION of the 2 clusters, using the operator "+". The result should be a list of 5 items (Giacomo, Gianni, Giovanni, Leopardi,  Leopoldo), but it DOES NOT WORK

    The formula I used is:

     sum( {<Nome=>+<FileDUE.Nome=>} FileDUE.StipendioDUE) + sum( {<Nome=>+<FileDUE.Nome=>} StipendioUNO)

2)  The DIFFERENCE of the 2 clusters, using the operator "-" (Cluster 1 - Cluster 2). The result should be a list of  all the elements included in the first cluster that are not in common: 2 items (Gianni & Giovanni).. , but it DOES NOT WORK

    The formula I used is:

     sum({<Nome= {}> - <FileDUE.Nome = {}>} StipendioUNO)

Could someone help me to sort out this issue?

Thanks

Alberto