(a)a continuous order book trading system that by means of an order book and a trading algorithm operated without human intervention matches sell orders with buy orders on the basis of the best available price on a continuous basis;
(b)a trading system combining elements of a continuous order book trading system, as referred to in point (a), and of a periodic auction trading system, as defined in point (2);
(2)‘periodic auction trading system’ means a trading system that matches orders on the basis of a periodic auction and a trading algorithm operated without human intervention.