Should I buy it? Help me understand

[Cyrien]

Research treaties and all other treaties that share something with the ally work by slowly building up to a max percentage. The default is 20%. It looks at what you are producing takes 20% of that and gives that to the ally. However you still get those points as well. Basically it creates research for those involved in them without taking anything away.

If you give or trade research the other person gets it and you still have it as well. Like copying a file. You copy it give the copy to your friend and they can use it and copy it as well if they want but you still keep your original.