- You may wish to consult
Onefor other, similarly-named pages.
In an emergency transmission sent by the TARDIS, the Thirteenth Doctor listed 5 things that she did in any worrying situation. The first was remembering that she would get through the situation, and that darkness never prevailed. (WC: Message from the Doctor)
Behind the scenes
Though AUDIO: The Haunting establishes that 1 is itself considered a prime number in the DWU, this is a point of contention among mathematicians. It would certainly have been considered a prime, in the story's time period of the 1890s. In particular, the entry for Number published in 1890 in the 9th edition of Encyclopædia Britannica stated that every positive number was either prime or composite, and explicitly listed 1 as prime. Nowadays, in the 21st century, 1 is instead generally considered as neither prime nor composite. To further complicate real-world existence of 1 as a number, there have even been periods of time - like Ancient Greek era - where 1 was in fact not even considered a number. This included notable mathematicians like Aristotle and Euclid.
- A. Reddick et al. The History of the Primality of One---A Selection of Sources. Accessed at http://primes.utm.edu/notes/one.pdf on 7.12.2015.
- Speusippus of Athens: A Critical Study With a Collection of the Related Texts and Commentary, Leonardo Tarán, 1981 (pgs 34-38)
- "What is the smallest Prime?", Chris K. Caldwell & Yeng Xiong; published in Journal of Integer Sequences Vol. 15 (2012)