# Basic relation help? [closed]

Hi I am trying to study for an exam and I have a template of the exam (given by the teacher) but he removes all the values etc

Let R be the relation on Z deﬁned by R = {(x, y) : ...}. Let S be the relation on Z deﬁned by S = {(x, y) : ...}.

What kind of values should I expect in a question like this?

• (a) Is R reﬂexive? Yes No
(b) Is R symmetric? Yes No
(c)Is R antisymmetric? Yes No

(d) Is R transitive? Yes No
(e) Is S reﬂexive? Yes No
(f) Is S symmetric? Yes No
(g) Is S antisymmetric? Yes No
(h) Is S transitive? Yes No

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You should expect the same kinds of values you've seen in class, on homework assignments, in the textbook if there is one, on last year's exam.... –  Gerry Myerson Nov 6 '11 at 3:23
Can't view previous years exams. The last exam the values were very different to the textbook/what was in class –  jolpi Nov 6 '11 at 3:29
Then I guess you'll just have to learn every possible set of values. Look, if you don't know what to expect from your teacher, how can we, who have never met her, have the foggiest idea? All you can really do is go over what you've seen, maybe look at a few other books or websites for examples, etc. –  Gerry Myerson Nov 6 '11 at 4:16
To be blunt, if you understand the properties of reflexivity, symmetry, antisymmetry, and transitivity of a relation, you don’t need to worry much about what kind of relations to expect. Unless your teacher is completely incompetent or unreasonable, they’ll be of a complexity comparable to (or even less than) those that you’ve already seen. (And if those questions are typical, you’re getting off very easily: I’d insist that you explain/justify your yes/no answers.) –  Brian M. Scott Nov 6 '11 at 8:44

## closed as not a real question by Austin Mohr, t.b., Asaf Karagila, Zev ChonolesDec 9 '11 at 6:10

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

For example:

$$R = \{ (x,y) | x,y \in \mathbb{Z}, x \leq y \}$$

or

$$R = \{ (x,y) | x,y \in \mathbb{Z}, x + y = 10 \}$$

You can be creative and invent some more examples. But I think given that you couldn't come up with your own examples means that you need to revise and understand what a relation is. Go look up the definition.

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