neurons and so on so this algorithm achieves what we want they go bit into detail how the actual error update here can be achieved and apparently neurons can achieve you know in the same layer to to adjust themselves to a given desired activation so this algorithm achieves it of course we don't have this G we don't have it and therefore we need to go a bit more complicated what they introduces the this following algorithm the goals are the same but now we assume we do not have a perfect inverse but we have something that is a bit like an