I respectfully disagree. If what you are saying is true, then the following should return 'a', but it returns blank:
{<uppercase *= {'A','X'}>}({<uppercase *= {'E','X'}>}({<uppercase *= {'B','C','D','X'}>}({<uppercase *= {'A','X'}>}Concat(lowercase))))
or why does this also return blank and not all results?
{<uppercase *= {'E'}>}({<uppercase *= {'B','C','D'}>}Concat(lowercase))
The above 2 results contradict your conclusion that "With the first two steps you get an empty set of field values for the selection. That means that all values are possible for the field 'uppercase' in the third step." A null set (set of no values) is not equivalent to the set of all values.
What I am saying is that the inheritance appears to be bugged. What you are suggesting is to not use inheritance, and while that works, it does not answer the question of whether or not inheritance is bugged. There are definitely ways of writing the expression to not use inheritance in the outer set or not using outer sets all together, but those features are not where I am seeing unexplained behavior.
Your example works because the inheritance issue appears to happen to set analysis after the null set happens.
{<Location *={'Canada'}>}
({<Department *= {'Groceries'}>}(ALT(SUM(Sales)/SUM(Cost),1)-1) * 0.6)
+ ({<Department *= {'Pharmacy'}>}(ALT(SUM(Sales)/SUM(Cost),1)-1)*0.4)
The issue is highlighed when you add a set after the null set, which breaks it (when selecting one department).
{<Location *={'Canada'}>}
({<Department *= {'Groceries'}>}({<Location *={'Canada'}>}ALT(SUM(Sales)/SUM(Cost),1)-1) * 0.6)
+ ({<Department *= {'Pharmacy'}>}({<Location *={'Canada'}>}ALT(SUM(Sales)/SUM(Cost),1)-1)*0.4)
These are all using *=, so there is no reason for <set1>(<set2>sum(...)) to work and <set1>(<set2>(<set1>sum(...))) to not work. They look mathematically equivalent to me. This is pretty much the same notation as what is used in the help text on inheritance.
I can give more examples... Why does the following return different results with no selections? (10% for the 1st one and 20% for the 2nd one)
({<Department *= {'Groceries'}>} ({<Location *= {'Canada'}>}(ALT(SUM(Sales)/SUM(Cost),1)-1)))
({<Department *= {'Groceries'}>*<Location *= {'Canada'}>} ({<Location *= {'Canada'}>}(ALT(SUM(Sales)/SUM(Cost),1)-1)))
This following expressions are returning 240, which is sum of sales in all departments. It doesn't even have a null set at any step of the inheritance. There appears to be no proper inheritance at all happening.
({<Department *= {'Groceries'}>*<Location *= {'Canada'}>} ({<Location *={'Canada'}>}SUM(Sales)))
({<Department *= {'Groceries'}>*<Location *= {'Canada'}>} ({<Sales *={"*"}>}SUM(Sales)))
({<Department *= {'Groceries'}>*<Location *= {'Canada'}>} (SUM({<Sales *={"*"}>}Sales)))
({<Department *= {'Groceries'}>*<Department *= {'Groceries'}>} ({<Location *={'Canada'}>}SUM(Sales)))
({<Department *= {'Groceries'}>*<Department *= {'Groceries'}>} (SUM({<Location *={'Canada'}>}Sales)))
It seems difficult to justify why the following would give different results:
({<Department *= {'Groceries'}>*<Department *= {'Groceries'}>} (SUM({<Location *={'Canada'}>}Sales)))
({<Department *= {'Groceries'}>} (SUM({<Location *={'Canada'}>}Sales)))
The intersection of 2 equivalent sets should be functionally equivalent to just itself. (i.e. <Department *= {'Groceries'}>*<Department *= {'Groceries'}> should be the same as <Department *= {'Groceries'}>) I don't see how that would cause inheritance to behave differently, unless it is attributable to a bug in the inheritance logic that handles intersections of sets involving the same field.
