1
1 (one, unit, unity) is a number representing a single unit of counting or measurement. 1 is the first and smallest positive integer. It is also sometimes considered the first of the infinite sequence of natural numbers, followed by 2, although by other definitions 1 is the second natural number. It commonly denotes the first, leading, or top thing in a group. 1 is by convention not considered a prime number.[citation needed]
In advanced mathematics, an identity element is often denoted 1, even if it is not a number.
As a word
Etymology
One originates from the Old English word an, derived from the Germanic root *ainaz, from the Proto-Indo-European root *oi-no- (meaning "one, unique").[1]
Modern usage
Linguistically, one is a cardinal number used for counting and expressing the number of items in a collection of things.[2] One is commonly used as a determiner for singular countable nouns, as in one day at a time.[3] One is also a gender-neutral pronoun used to refer to an unspecified person or to people in general as in one should take care of oneself.[4] Words that derive their meaning from one include alone, which signifies all one in the sense of being by oneself, none meaning not one, once denoting one time, and atone meaning to become at one with the someone. Combining alone with only (implying one-like) leads to lonely, conveying a sense of solitude.[5] Other common numeral prefixes for the number 1 include uni- (e.g., unicycle, universe, unicorn), sol- (e.g., solo dance), derived from Latin, or mono- (e.g., monorail, monogamy, monopoly) derived from Greek.[6][7]
In mathematics
- 1 is the second natural number after 0 (zero).
- 0! is equal to 1, as a special case of the empty product.[8]
- In algebraic structures such as multiplicative groups and monoids the identity element is often denoted 1, although e (from the German Einheit, "unity") is also used.
- A matrix of ones or all-ones matrix is defined as a matrix composed entirely of 1s.[9]
- 1 is generally not considered a prime.
- In category theory, 1 is the terminal object of a category if there is a unique morphism.[10]
- 1 is the value of Legendre's constant.
- 1 is the most common leading digit in many sets of data (occurring about 30% of the time), a consequence of Benford's law.[11]
- 1 is the only known Tamagawa number for a simply connected algebraic group over a number field.[12][13]
Table of basic calculations
Multiplication | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1000 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 × x | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 1000 |
Division | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 ÷ x | 1 | 0.5 | 0.3 | 0.25 | 0.2 | 0.16 | 0.142857 | 0.125 | 0.1 | 0.1 | 0.09 | 0.083 | 0.076923 | 0.0714285 | 0.06 |
x ÷ 1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
Exponentiation | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 20 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1x | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
x1 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 20 |
Symbols and representation
Among the earliest known record of a numeral system, is the Sumerian decimal-sexagesimal system on clay tablets dating from the first half of the third millennium BCE.[14] The Archaic Sumerian numerals for 1 and 60 both consisted of horizontal semi-circular symbols.[15] By c. 2350 BCE, the older Sumerian curviform numerals were replaced with cuneiform symbols, with 1 and 60 both represented by the same symbol . The Sumerian cuneiform system is a direct ancestor to the Eblaite and Assyro-Babylonian Semitic cuneiform decimal systems.[16] Surviving Babylonian documents date mostly from Old Babylonian (c. 1500 BCE) and the Seleucid (c. 300 BCE) eras.[14] The Babylonian cuneiform script notation for numbers used the same symbol for 1 and 60 as in the Sumerian system.[17]
The most commonly used glyph in the modern Western world to represent the number 1 is the Arabic numeral, a vertical line, often with a serif at the top and sometimes a short horizontal line at the bottom. It can be traced back to the Brahmic script of ancient India, as represented by Ashoka as a simple vertical line in his Edicts of Ashoka in c. 250 BCE.[18] This script's numeral shapes were transmitted to Europe via the Maghreb and Al-Andalus during the Middle Ages, through scholarly works written in Arabic.[citation needed] In some countries, the serif at the top may be extended into a long upstroke as long as the vertical line. This variation can lead to confusion with the glyph used for seven in other countries and so to provide a visual distinction between the two the digit 7 may be written with a horizontal stroke through the vertical line.[citation needed]
In modern typefaces, the shape of the character for the digit 1 is typically typeset as a lining figure with an ascender, such that the digit is the same height and width as a capital letter. However, in typefaces with text figures (also known as Old style numerals or non-lining figures), the glyph usually is of x-height and designed to follow the rhythm of the lowercase, as, for example, in .[19] In old-style typefaces (e.g., Hoefler Text), the typeface for numeral 1 resembles a small caps version of I, featuring parallel serifs at the top and bottom, while the capital I retains a full-height form. This is a relic from the Roman numerals system where I represents 1.[20][21] The modern digit '1' did not become widespread until the mid-1950s. As such, many older typewriters do not have dedicated key for the numeral 1 might be absent, requiring the use of the lowercase letter l or uppercase I as substitutes.[21] The lower case "j" can be considered a swash variant of a lower-case Roman numeral "i", often employed for the final i of a "lower-case" Roman numeral. It is also possible to find historic examples of the use of j or J as a substitute for the Arabic numeral 1.[22][23][24][25]
In technology
In digital technology, data is represented by binary code, i.e., a base-2 numeral system with numbers represented by a sequence of 1s and 0s. Digitised data is represented in physical devices, such as computers, as pulses of electricity through switching devices such as transistors or logic gates where "1" represents the value for "on". As such, the numerical value of true is equal to 1 in many programming languages.[26][27]
In science
- Dimensionless quantities are also known as quantities of dimension one.
- Hydrogen, the first element of the periodic table, has an atomic number of 1.
- Group 1 of the periodic table consists of the alkali metals.
- Period 1 of the periodic table consists of just two elements, hydrogen and helium.
In philosophy
In the philosophy of Plotinus (and that of other neoplatonists), The One is the ultimate reality and source of all existence.[28] Philo of Alexandria (20 BC – AD 50) regarded the number one as God's number, and the basis for all numbers ("De Allegoriis Legum", ii.12 [i.66]).
The Neopythagorean philosopher Nicomachus of Gerasa claimed that one is not a number, but the source of number. He also believed the number two is the embodiment of the origin of otherness. His number theory was recovered by Boethius in his Latin translation of Nicomachus's treatise Introduction to Arithmetic.[29]
See also
References
- ^ "Online Etymology Dictionary". etymonline.com. Douglas Harper. Archived from the original on 2013-12-30. Retrieved 2013-12-30.
- ^ Hurford 1994, pp. 23–24.
- ^ Huddleston, Pullum & Reynolds 2022, p. 117.
- ^ Huddleston, Pullum & Reynolds 2022, p. 140.
- ^ Conway & Guy 1996, pp. 3–4.
- ^ Chrisomalis, Stephen. "Numerical Adjectives, Greek and Latin Number Prefixes". The Phrontistery. Archived from the original on 2022-01-29. Retrieved 2022-02-24.
- ^ Conway & Guy 1996, p. 4.
- ^ Graham, Knuth & Patashnik 1988, p. 111.
- ^ Horn & Johnson 2012, p. 8.
- ^ Awodey 2010, p. 33.
- ^ Miller 2015, p. 4.
- ^ Gaitsgory & Lurie 2019, pp. 204–307.
- ^ Kottwitz 1988.
- ^ a b Conway & Guy 1996, p. 17.
- ^ Chrisomalis 2010, p. 241.
- ^ Chrisomalis 2010, p. 244.
- ^ Chrisomalis 2010, p. 249.
- ^ Acharya, Eka Ratna (2018). "Evidences of Hierarchy of Brahmi Numeral System". Journal of the Institute of Engineering. 14: 136–142. doi:10.3126/jie.v14i1.20077.
- ^ Cullen 2007, p. 93.
- ^ "Fonts by Hoefler&Co". www.typography.com. Retrieved 2023-11-21.
- ^ a b Company, Post Haste Telegraph (April 2, 2017). "Why Old Typewriters Lack A "1" Key".
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has generic name (help) - ^ Köhler, Christian (November 23, 1693). "Der allzeitfertige Rechenmeister" – via Google Books.
- ^ "Naeuw-keurig reys-boek: bysonderlijk dienstig voor kooplieden, en reysende persoonen, sijnde een trysoor voor den koophandel, in sigh begrijpende alle maate, en gewighte, Boekhouden, Wissel, Asseurantie ... : vorders hoe men ... kan reysen ... door Neederlandt, Duytschlandt, Vrankryk, Spanjen, Portugael en Italiën ..." by Jan ten Hoorn. November 23, 1679 – via Google Books.
- ^ "Articvli Defensionales Peremptoriales & Elisivi, Bvrgermaister vnd Raths zu Nürmberg, Contra Brandenburg, In causa die Fraiszlich Obrigkait [et]c: Produ. 7. Feb. Anno [et]c. 33". Heußler. November 23, 1586 – via Google Books.
- ^ August (Herzog), Braunschweig-Lüneburg (November 23, 1624). "Gustavi Seleni Cryptomenytices Et Cryptographiae Libri IX.: In quibus & planißima Steganographiae a Johanne Trithemio ... magice & aenigmatice olim conscriptae, Enodatio traditur; Inspersis ubique Authoris ac Aliorum, non contemnendis inventis". Johann & Heinrich Stern – via Google Books.
- ^ Woodford, Chris (2006), Digital Technology, Evans Brothers, p. 9, ISBN 978-0-237-52725-9, retrieved 2016-03-24
- ^ Godbole 2002, p. 34.
- ^ Olson 2017.
- ^ British Society for the History of Science (July 1, 1977). "From Abacus to Algorism: Theory and Practice in Medieval Arithmetic". The British Journal for the History of Science. 10 (2). Cambridge University Press: Abstract. doi:10.1017/S0007087400015375. S2CID 145065082. Archived from the original on May 16, 2021. Retrieved May 16, 2021.
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