A goal of apt and problem that has to overcome Yum is more efficiency in dependancy analysis and manage it according to the situation, for example , I can install a package called "A" that depend of other called "B" and "C" is duty of Yum install B and C (B <-A-> C), then if I want to install other package called "D" and this depends only of B Yum will install only D (D<->B) because B just was installed by A, Just here no problem, neverthless I want via Yum _only_ uninstall "A", this will remove B, C and D but "D" not have some inherency in A, so why Yum uninstall B and D?