Exponential slashing

[chevdor]

In order to eliminate bad validators very quickly while giving honest validators also a chance to mess up a few time, I propose to use a non linear slashing calculation.

So instead of a fixed 10k penalty, we could use:
slash_amount = a x (cruelty ^ n) + c
with:

• a = 1000
• cruelty = 3
• c = -1000

cruelty can be adjusted for harder/softer penalties.

n starts at 0 and increment for each slashing.

That gives us a mercyful penalty at first:

n=1 => 2000 (first slashing)
n=2 => 8000

But also increase then very fast:

n=3 => 26k
n=4 => 80k
n=5 => 242k

[chevdor]

We can by the way use the same implementation for a result very similar to what we have today with:

• a =10000000
• b = 1.001
• c = -a

[gavofyork]

exponential slashing is in #554