# S.O.S. Mathematics CyberBoard

Your Resource for mathematics help on the web!
 It is currently Sat, 18 May 2013 17:19:54 UTC

 All times are UTC [ DST ]

 Page 1 of 1 [ 6 posts ]
 Print view Previous topic | Next topic
Author Message
 Post subject: URGENT!!! Relation that is asymmetric, symmetric andPosted: Fri, 21 Oct 2011 15:15:53 UTC
 Member

Joined: Sat, 20 Aug 2011 12:38:23 UTC
Posts: 39
Hi guys, i am very new to relations.
Code:
Find a binary relation on Z251 which is not reflexive but is symmetric, antisymmetric and transitive.

My answer would be that it is a empty set.

Say R = {(1,1), (1,2), (2,2), (2,4)}
a R b <=> There exists c belong such that b = c x a
However, this relation would not be asymmetric.

Another answer i have would be that R = Empty set X Z251

Top

 Post subject: Re: URGENT!!! Relation that is asymmetric, symmetric andPosted: Sat, 22 Oct 2011 04:41:35 UTC
 Member of the 'S.O.S. Math' Hall of Fame

Joined: Wed, 1 Oct 2003 04:45:43 UTC
Posts: 9631
I agree that the empty relation satisfies all of those properties.

Top

 Post subject: Re: URGENT!!! Relation that is asymmetric, symmetric andPosted: Sat, 22 Oct 2011 04:48:04 UTC
 Member

Joined: Sat, 20 Aug 2011 12:38:23 UTC
Posts: 39
Well, but what would be a proper answer for this?

Top

 Post subject: Re: URGENT!!! Relation that is asymmetric, symmetric andPosted: Sat, 22 Oct 2011 05:41:49 UTC
 Moderator

Joined: Mon, 29 Dec 2008 17:49:32 UTC
Posts: 6003
Location: 127.0.0.1, ::1 (avatar courtesy of UDN)
aceminer wrote:
Well, but what would be a proper answer for this?

What is not proper about the empty relation?

In fact, you will necessarily have some element that is not related to anything else.

_________________

Top

 Post subject: Re: URGENT!!! Relation that is asymmetric, symmetric andPosted: Sat, 22 Oct 2011 06:51:32 UTC
 Member

Joined: Sat, 20 Aug 2011 12:38:23 UTC
Posts: 39
Hmm... what i meant would be how should i present this in an answer which is proper. Or would an answer to be the question simply be it is an empty relation?

Top

 Post subject: Re: URGENT!!! Relation that is asymmetric, symmetric andPosted: Mon, 24 Oct 2011 22:04:08 UTC
 Moderator

Joined: Wed, 30 Mar 2005 04:25:14 UTC
Posts: 12071
Location: Austin, TX
aceminer wrote:
Hmm... what i meant would be how should i present this in an answer which is proper. Or would an answer to be the question simply be it is an empty relation?

All universal quantifier statements about empty sets are true.

_________________
(\ /)
(O.o)
(> <)
This is Bunny. Copy Bunny into your signature to help him on his way to world domination

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 1 [ 6 posts ]

 All times are UTC [ DST ]

#### Who is online

Users browsing this forum: No registered users

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forum

Search for:
 Jump to:  Select a forum ------------------ High School and College Mathematics    Algebra    Geometry and Trigonometry    Calculus    Matrix Algebra    Differential Equations    Probability and Statistics    Proposed Problems Applications    Physics, Chemistry, Engineering, etc.    Computer Science    Math for Business and Economics Advanced Mathematics    Foundations    Algebra and Number Theory    Analysis and Topology    Applied Mathematics    Other Topics in Advanced Mathematics Other Topics    Administrator Announcements    Comments and Suggestions for S.O.S. Math    Posting Math Formulas with LaTeX    Miscellaneous