So, first we're told that g' is the "legitimately" remaining gas. But then we're told that g*, where g* >= g', is "the total gas that remains". If g' is the remaining gas, how do we add to it to arrive at the "total gas that remains"? What is the difference between the "legitimately remaining gas" and the "total gas remaining"? Is g* not greater than or equal to the amount of gas actually remaining? And who's meant to make up this potential difference, the miner?
Additionally, what is the significance of the (Tg-g')/2? Is this halving just arbitrary? Quite confused by this equation.