well, thank you for your answer!
i fully agree with what you writing.. but the problem is not the internal storage ir the call by value|name|referenace issue.. itīs about detecting the relations and reduce the branches..

[A] => [1, 2]
[A] => [1]
[download]

is the same like

[A] => [1, 2]
[download]

i have to mention that A is already related with 1 for that the second A => 1 relation is redundant but it has to be nonredundant :)