Four Small Universal Turing Machines

We present small polynomial time universal Turing machines with state-symbol pairs of (5, 5), (6, 4), (9, 3) and (18, 2). These machines simulate our new variant of tag system, the bi-tag system and are the smallest known universal Turing machines with 5, 4, 3 and 2-symbols respectively. Our 5-symbol machine uses the same number of instructions (22) as the smallest known universal Turing machine by Rogozhin.

• Type: Conference
• Year: 2007
• Where: MCU
• Authors: Turlough Neary, Damien Woods
• Keywords: Hardware, MCU 2007, State-symbol Pairs, Time Universal Turing, Universal Turing Machine