high-frequency algorithmic trading technique

42means an algorithmic trading technique characterised by:

1. (1) infrastructure intended to minimise network and other types of latencies, including at least one of the following facilities for algorithmic order entry: co-location, proximity hosting or high-speed direct electronic access;
2. (2) system-determination of order initiation, generation, routing or execution without human intervention for individual trades or orders; and
3. (3) high message intraday rates which constitute orders, quotes or cancellations.

[Note: article 4(1)(40) of MiFID]