Elemental Penetration

I am looking for an answer regarding how Elemental Penetration works.

So right now i have 93% elemental penetration from omniscience.

If I would have had 100% elemental penetration does that mean that I negate all the resistance on the mob ? Or that I take his resistances.

So if a Mob has 100% cold resistance ---> With 100% elemental penetration does it mean he has 0% or he goes to whatever negative value is max that he can have.

Also how does elemental penetration work with awakened cold penetration for example. I have 93% from omniscience, does the elemental penetration go to 93%+40 on the gem, bringing the mob to -33% cold resistance ? Or does anything over 100% elemental penetration doesn't really stack ?

Also is there a cap on to how much you can reduce the mobs resistances ?


Thanks for the answers.