On Sat, May 9, 2015 at 4:36 AM, Gregory Maxwell <gmaxwell@gmail.com> wrote:

> An example would
> be tx_size = MAX( real_size >> 1,  real_size + 4*utxo_created_size -
> 3*utxo_consumed_size).


This could be implemented as a soft fork too.

* 1MB hard size limit
* 900kB soft limit

S = block size
U = UTXO_adjusted_size = S + 4 * outputs - 3 * inputs

A block is valid if S < 1MB and U < 1MB

A 250 byte transaction with 2 inputs and 2 outputs would have an adjusted
size of 252 bytes.

The memory pool could be sorted by fee per adjusted_size.

 Coin selection could be adjusted so it tries to have at least 2 inputs
when creating transactions, unless the input is worth more than a threshold
(say 0.001 BTC).

This is a pretty weak incentive, especially if the block size is
increased.  Maybe it will cause a "nudge"