Open Interval

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open interval

[′ō·pən ′in·tər·vəl]
An open interval of real numbers, denoted by (a,b), consists of all numbers strictly greater than a and strictly less than b.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Open Interval


the set of points between two given points. In other words, if a and b are the coordinates of the two given points, then the set of points having coordinates x such that axb is an open interval. An open interval does not contain its end points and is denoted by (a, b). In contrast, the closed interval [a, b] contains its end points and consists of the points having coordinates x such that a ≤ x ≤ b.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The measure m(a, b) of an open interval (a, b) in R is the length b - a of this interval.
The state transition matrix for the homogeneous linear system (1.2) on the open interval J is the family of fundamental matrix solutions t [right arrow] [PHI](t, r) parametrized by r [member of] J such that [PHI](r, r) = I.
problem (1) admits at least three weak solutions in X and, moreover, for each h > 1, there exists an open interval
Yet again, any real number x in the open interval (a, b) satisfies [PI](x, g(i + 1), ..., g(i + n)) = [sigma].
i.e., of non-empty intervals of [R.sub.[greater than or equal to] 0] where: (i) [/.sub.0] ={0}; (ii) singular and open intervals alternate; (iii) succesive intervals [/.sub.j] and [/.sub.j+1] are adjacent for all j [greater than or equal to] 0, (iv) if infinite, the sequence of intervals is progressive, i.e., for every t[member of][R.sub.[greater than or equal to] 0], there exists [member of] N such that t[member of][/.sub.j].
It represents the open interval corresponding to the saturated zone of the sediments.
In particular, we say that the composition F(f(x)) exists and is equal to h on the open interval (a, b) if
Assume that the function f: I [subset] R [right arrow] R for an open interval I has a simple root [alpha] [member of].
Consider a 'smooth function' f in an open interval containing a point at x = [x.sub.0] below in Figure 1:
[GAMMA](s) exist the least value in open interval [1,2], and monotone decreasing at the left side of the point, at the right side of the point monotone increasing.
Let ube a strictly increasing three times continuously differentiate function defined in an open interval I.
The [3-observers.sup.*] in the Euclidean 3-space -[[SIGMA].sup.*] of the negative universe "observe" intrinsic Special Relativity ([phi]SR) and hence observe Special Relativity (SR) for intrinsic angles [phi][psi] in the open interval (-[pi]/2, [pi]/2) in Fig.