enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Real number - Wikipedia

    en.wikipedia.org/wiki/Real_number

    The long real line pastes together ℵ 1 * + ℵ 1 copies of the real line plus a single point (here ℵ 1 * denotes the reversed ordering of ℵ 1) to create an ordered set that is "locally" identical to the real numbers, but somehow longer; for instance, there is an order-preserving embedding of ℵ 1 in the long real line but not in the real ...

  3. Domain of a function - Wikipedia

    en.wikipedia.org/wiki/Domain_of_a_function

    Graph of the real-valued square root function, f(x) = √ x, whose domain consists of all nonnegative real numbers. In mathematics, the domain of a function is the set of inputs accepted by the function. It is sometimes denoted by ⁡ or ⁡, where f is the function. In layman's terms, the domain of a function can generally be thought of as ...

  4. Positive real numbers - Wikipedia

    en.wikipedia.org/wiki/Positive_real_numbers

    In mathematics, the set of positive real numbers, > = {>}, is the subset of those real numbers that are greater than zero. The non-negative real numbers , R ≥ 0 = { x ∈ R ∣ x ≥ 0 } , {\displaystyle \mathbb {R} _{\geq 0}=\left\{x\in \mathbb {R} \mid x\geq 0\right\},} also include zero.

  5. Real analysis - Wikipedia

    en.wikipedia.org/wiki/Real_analysis

    The real numbers have various lattice-theoretic properties that are absent in the complex numbers. Also, the real numbers form an ordered field, in which sums and products of positive numbers are also positive. Moreover, the ordering of the real numbers is total, and the real numbers have the least upper bound property: Every nonempty subset of ...

  6. Real coordinate space - Wikipedia

    en.wikipedia.org/wiki/Real_coordinate_space

    Cartesian coordinates identify points of the Euclidean plane with pairs of real numbers. In mathematics, the real coordinate space or real coordinate n-space, of dimension n, denoted R n or , is the set of all ordered n-tuples of real numbers, that is the set of all sequences of n real numbers, also known as coordinate vectors.

  7. List of types of numbers - Wikipedia

    en.wikipedia.org/wiki/List_of_types_of_numbers

    All rational numbers are real, but the converse is not true. Irrational numbers (): Real numbers that are not rational. Imaginary numbers: Numbers that equal the product of a real number and the imaginary unit , where =. The number 0 is both real and imaginary.

  8. De Bruijn–Erdős theorem (graph theory) - Wikipedia

    en.wikipedia.org/wiki/De_Bruijn–Erdős_theorem...

    A frequent goal in graph coloring is to minimize the total number of colors that are used; the chromatic number of a graph is this minimum number of colors. [1] The four-color theorem states that every finite graph that can be drawn without crossings in the Euclidean plane needs at most four colors; however, some graphs with more complicated ...

  9. Sign function - Wikipedia

    en.wikipedia.org/wiki/Sign_function

    The signum function of a real number is a piecewise function which is defined as follows: [1] ⁡:= {<, =, > The law of trichotomy states that every real number must be positive, negative or zero. The signum function denotes which unique category a number falls into by mapping it to one of the values −1 , +1 or 0, which can then be used in ...