I came to a solution of NXT 'rich get richer' problem (when an account have no activity at all, but forging all the time, in the limit tending to infinity he will acquire all of the coins, and during this his forging rate is constantly increasing).

Not sure it wasn't discussed before. Haven't looked through all threads and forums.

Actually it could be applied to any PoS coin with NXT alike 'forging' algorithm.

But this solution is kind of another 'paradigm-shift' (+1 to using crypto-currencies in general

, and I'm not sure average Joe will accept it.

The idea is to add, lets call it, 'forging energy' to any account balance. It could be positive, equal to zero, or negative.

Each time the forger account receives transaction fees, his 'energy' balance is decreased by the received amount.

Each time someone is making a transaction, his 'energy' balance is increased by payed fee.

Example:

X has 1000 coins

Y has 1000 coins

Z has 2000 coins

All with initial zero energy.

X is sending 1000 to Y, paying 1 coin fee. Z is chosen to be the forger.

Result:

X - 0 coins, 1 energy

Y - 1999 coins, 0 energy

Z - 2001 coins, -1 energy

When the process of choosing a next forger is taking place, each node is measured not by his balance, but by his balance value + energy value.

What do we have from this?

1) Each received fee does not change the ratio between forger 'forging ability' and 'forging ability' of all others taken together.

2) Each fee payed increases the 'forging ability' of the node. (If not counting in the amount he actually send off from his account).

Now, the main thing.

Energy 'units', positive or negative, could be sent the same way as coins. But only as an addition to a coin transaction.

With any proportions/amounts, with only two rules:

1) Modulo of negative energy of the account can't be more than it's balance.

2) Modulo of added negative energy to a transaction can't be more than the amount of coins being sent.

From this we have another interesting consequences:

1) It's impossible to get rid of your negative energy by yourself without giving it to someone else. (Someone could help you by sending his positive energy to you).

2) You can be a forger with zero balance, just by having positive energy.

3) Each receiver decides by himself how to treat received negative/positive energy.

4) Energy is getting it's own value, as a 'forging tool' if it is positive. Some kind of pure PoS 'ASIC'. Or as 'waste' if it is negative, for which you can pay somehow someone for taking it from you.

5) Even when someone is getting rid of his negative energy the initial ratio of his 'forging ability' compared to others taken together is still the same.

Negative consequences:

1) Increased complexity of PoS crypto-currency system.

2) Forged coins are not increasing your forging strength.

3) Anyone must deal by himself with situation of receiving negative energy.

4) Someone could not notice added negative energy to coins he received.

5) Asset exchange trading and smart contracts becomes more complicated.