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Is there a term for referring to a real number in the [0, 1] interval? Examples:

(Sorry for dumby question, but I don't find resources!)

1
0.5
.3
0.9

I've heard of decimal, but I think it's on the [0, 1) interval.

  • is this a computer science question ? –  Jul 15 '17 at 12:14
  • @RoddyMacPhee Nope, I'm asking for a term that I can use to refer to floating numbers (w/o decimal number) that start from 0 and end at 1. –  Jul 15 '17 at 12:16
  • so an interval ? –  Jul 15 '17 at 12:17
  • @RoddyMacPhee Yea. I need a term for the { 0, ..., 1 } interval. –  Jul 15 '17 at 12:18
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    I don't know of any particular name, but $0.9999999\dots$, usually denoted $0.\bar{9}$, is equal to $1$. (also, the notation for the interval is $[0,1]$, not ${0,\dots,1}$ which would refer usually to all integers between $0$ and $1$ included, i.e. the set ${0,1}$) – Clement C. Jul 15 '17 at 12:18
  • @ClementC. Nice! I never heard about that. If so decimal is a good term... –  Jul 15 '17 at 12:19
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    https://en.wikipedia.org/wiki/Unit_interval is the interval [01] including the endpoints –  Jul 15 '17 at 12:20
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    @Matheus https://en.wikipedia.org/wiki/0.999... – Clement C. Jul 15 '17 at 12:20
  • Thanks, this helped me as well. –  Jul 15 '17 at 12:25
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    @Matheus By any chance are you simply referring to the interval $[0,1)$ where $1$ is not included but every nonnegative number strictly less than $1$ is included? If so, then this interval does not have a maximum value, but saying "the maximum value is 0.9999..." would be plausible as a naive way to describe this concept. (Most people who haven't studied analysis would not realize it is possible for a bounded set to not have a maximum.) – Erick Wong Jul 15 '17 at 13:32
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    In oreder to specify that $x$ is a real number in the interval $[0,1]$, one usually writes $x\in[0,1]$. – Hagen von Eitzen Jul 15 '17 at 14:06
  • @ErickWong The interval [0, 1) was what I though decimal numbers were composed of. I really want to include 1. –  Jul 15 '17 at 16:40
  • @HagenvonEitzen Thanks, I'll remind me about this expression. Actually I need a term for direct reference. –  Jul 15 '17 at 16:43
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    The capital letter $ I$ is often used for the set $[0,1$], especially when it needs to be mentioned repeatedly. But it is not good to use $I$ for $[0,1] $without saying so, as it is not a universal convention. – DanielWainfleet Jul 15 '17 at 19:12

2 Answers2

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Positive fractional numbers are those in $[0,1[$.

Decimal is, properly speaking, related to the rapresentation of a number, not to the number itself (the decimal representation) to distinguish it from other rapresentations (binary, hexadecimal, ...).

There is not a single english word to name a generic number in $[0,1]$: you can say positive fractional or unity.

Please note that, $0.\bar{9}=1$ exactly. It is not an approximation.

simone.mancini
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If you are just searching for a word: You could write

"Real numbers (rational or irrational) in the interval $[0,1]$ will be called fractions for short."

Christian Blatter
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