*In Zeno's Paradox of Achilles and the Tortoise, Achilles can never outrun a tortoise having a head start, since he must always reach the point where the tortoise once was, but departed, with the consequence that the tortoise can never be overtaken. This paradox expresses the idea that the distance between Achilles and the tortoise can never be zero; and, therefore, zero can't be transcended to change the sign of that distance. This was my favorite paradox when I was a high school student. (Modified Wikimedia Commons image by Daniele Pugliesi. Click for larger image.)*

Moving ahead into Anno Domini times, Ptolemy (c.100-c.170) was using a symbol for zero, a small circle with a line above it, around 150 AD in his Almagest. Zero in Latin texts throughout the Middle Ages was much different, being essentially the letter,

*Proposition 4 from De summatione innumerabilium progressionum (1738) by Leonhard Euler, illustrating the use of the symbol for zero. In translation it reads, "§4. This form is assumed as the general term of a certain progression: ∫((1-x ^{n})/(1-x))dx; which clearly integrated, thus so that it becomes equal to zero if x = 0, and on putting x = 1, the term of order n is given." Latin text from Ref. 1, and English translation from Ref. 2.[1-2]*

All people are familiar with the basic mathematical symbols for addition (+), subtraction (−), multiplication (×), division (÷), and the square root (√), and most technologists know also the symbols for summation (∑) and integration (∫), as well as those for comparison; i.e., less than (<), greater than (>), less than or equal (≤), and greater than or equal (≥). Lesser known are the basic symbols of symbolic logic. Two of these are contortions of Roman alphabet letters; namely, the existential quantification operator (∃, normally expressed as "there exists," as in ∃(x), "there exists an x"), and the universal quantification operator (∀, "for all." as in ∀(x), "for all x"). Other symbols in mathematical logic are the symbols for "and" (⋀), "or" (⋁), and also material conditional (⊃, also written as →) that's used in statements such as modus ponens; viz,

If P, then Q (P⊃Q)You can view many unicode characters in the category, "Math Symbol," at Ref. 3.[3] Landon D. C. Elkind of the University of Alberta (Edmonton, Alberta, Canada), and Richard Zach of the University of Calgary (Calgary, Alberta, Canada) have recently published a lengthy paper on arXiv in which they've investigated the origin of the symbol for logical disjunction ("or," ⋁).[4] It has been suggested by many historians that, just as

P is true

Therefore, Q is true.

*Excerpt from Principia Mathematica by Alfred North Whitehead (1861-1947) and Bertrand Russell (1872-1970) showing use of the disjunction symbol. (Portion of a scan of page 13 of my copy.[5])*

While Peano made a case for using a

"The appealing short story told that our '∨' for disjunction comes from the Latin vel and is due to Leibniz is not well-supported by the textual record. It was Russell, not Leibniz, who first systematically used ‘∨’ for disjunction, and it is more likely given Russell’s logical habits that this choice of notation was to stress the analogy of propositional addition with class union."[4]

- Leonhard Euler, "De summatione innumerabilium progressionum," Commentarii academiae scientiarum Petropolitanae, vol. 5 (1730/31), published 1738, pp. 91-105, from the Euler Archive.
- Leonhard Euler, "De summatione innumerabilium progressionum (Concerning the Summation of Innumerable Progressions)," Commentarii academiae scientiarum Petropolitanae, vol. 5 (1730/31), published 1738, pp. 91-105, Translated and annotated by Ian Bruce.
- List of Unicode Characters of Category "Math Symbol," Compart AG Website.
- Landon D. C. Elkind, and Richard Zach, "The Genealogy of ⋁, arXiv, December 14, 2020.
- Alfred North Whitehead and Bertrand Russell, Principia Mathematica to *56, Cambridge University Press, Reprint edition, January 1, 1964, 410pp.