Talk:Kayle/@comment-4881935-20130118012005/@comment-2124153-20130118211449

Put another way: multiplicative stacking results in diminishing returns, but Armor/MR effective health scaling is linear. This implies that there is a value for Armor/MR where a given amount of multiplicative waste, is overcome by the added effects of reducing linear-scaling Armor/MR by a percentage.

It turns out that the example I chose -- which was not an accident, by the way -- details one such scenario. It doesn't hold forever: as I said, if the target has 100 Armor instead of 200 Armor, you no longer have synergy, because the whole is less than the sum of the parts.