Capital ships we all love them however I was wondering how xp is assigned?

1) they only get xp for their own kills in a system
2) they get full xp for any ship killed in a system they are in even if it is by defences or other ships.
3) they get full xp for all kills they are involved in eg. ones where they have damaged the ships in question.

I have noticed that if 2 C ships are on a target the xp is split 50/50 to each ship.