Technology spreading and advanced diplomancy

-Factions friendly enough should have diplomancy proposal about sharing, trading or cooprate-researching technologies. 

-Knowledge should spread on its own, more or less. After any faction achived a technology, other factions which have connects to it should have a small boost while researching the same technology. It is based on four factors:

How close the relation is between the factions. (At war against each other is somehow a close state because you need to observe and study your enemy constantly. At least it's closer than never met.)

How similar the dominating ideologies are.

How far the distance from each other's nearest colony.

And of course, a law about blockade all technology secrets will slow the spreading.

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updated Jan 18th thanks for the inspiration from fantasyfr:

I'm asuming 4 levels of scientific interaction:

-Blockade & Sabotage: If you are completely incooprate with another player, you can blockade your technological secrets from them, but still you can use spy to try to steal their secret to boost your research - if they already have the technology that you are aiming to research. If you successfully managed to do that, you can delay or set back their research progress too.

-Contact & Study: Default technology spreading effect when one member of the relationship is researching a technology that others already have. Tech trade still work if everyone in this relationship is researching a technology that nobody already own.

-Scientific Business: Your allie could use your researched techology as a leased patent, right after you made a deal about it. All the effect of "Contact & Study" level will continue to work too. But even if they finished their own research on the leased technology, they still need to finish the contract, unless they want to break it.

-Unified Coopration: You can directly trade your technology permanently with or without a price with your partner. If both of you are researching a same technology at the same time, then with right policy and actions, some of your tech points will be summed into each other's research ability during this project. Therefor both of you will get a significant boost on the current research project. All the effect of "Scientific Business" level will continue to work too.