Define participation-adjusted inflation curve

[Zerim]

The protocol will implement a participation reward, paid via inflation, which varies according to how many tokens are staked productively in the network.

We must define the curve which relates the participationReward to targetParticipation and actualParticipation, and any additional parameters for that curve which may be set via governance.

Requirements:

• if actualParticipation === targetParticipation, then participationRewardRate = 0.
• if actualParticipation === 0 then participationRewardRate = 0. (There is noone to receive the award).

[jtremback]

I'm having a tough time relating this to stuff in https://github.com/graphprotocol/research/tree/master/specs/graph-protocol-v1/mechanism-design .

In this issue when you refer to participationReward do you actually mean participationRewardRate?

[Zerim]

@jtremback Correct, reworded participationReward --> participationRewardRate above.