Problem 1. A set ICR is called an interval if for all triples of real numbers x, y, and z such that x < z < y, if x € I and y € I then z € I. Prove that every interval takes exactly one of the following nine forms: (-∞,b), (-∞,b], (a,b), (a,b], [a,b), [a,b], (a, ∞), [a, ∞), or (-∞, ∞).

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
Problem 1. A set I ≤ R is called an interval if for all triples of real numbers x, y,
and z such that x < z < y, if x € I and y € I then z € I. Prove that every interval takes
exactly one of the following nine forms:
(-∞,b), (-∞,b], (a,b), (a,b], [a,b), [a,b], (a, ∞), [a, ∞), or (-∞, ∞).
(Hint: You have to consider an arbitrary set I satisfying the condition in the problem and
prove something about it. Consider cases according to whether I is (unbounded above /
bounded above and contains its sup / bounded above and does not contain its sup), and
similarly for below. You should have 3-3 = 9 cases.")
Transcribed Image Text:Problem 1. A set I ≤ R is called an interval if for all triples of real numbers x, y, and z such that x < z < y, if x € I and y € I then z € I. Prove that every interval takes exactly one of the following nine forms: (-∞,b), (-∞,b], (a,b), (a,b], [a,b), [a,b], (a, ∞), [a, ∞), or (-∞, ∞). (Hint: You have to consider an arbitrary set I satisfying the condition in the problem and prove something about it. Consider cases according to whether I is (unbounded above / bounded above and contains its sup / bounded above and does not contain its sup), and similarly for below. You should have 3-3 = 9 cases.")
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,