Recent questions tagged relations

2 2 votes
2 2 answers
703
703 views
Define $\mathcal{R}$ the binary relation on $\mathbb{N} \times \mathbb{N}$ to mean $(a, b) \mathcal{R}(c, d)$ iff $b \mid d$ and $a \mid c$$\mathcal{R}$ is symmetric but ...
1 1 vote
1 1 answer
600
600 views
Let $A$ be any set. Subset Relation on $\mathrm{P}(\mathrm{A})$ is Anti-symmetric?
1 1 vote
1 1 answer
874
874 views
Define $\mathcal{R}$ the binary relation on $\mathbb{N} \times \mathbb{N}$ to mean $(a, b) \mathcal{R}(c, d)$ iff $b \mid d$ and $a \mid c$
1 1 vote
1 1 answer
830
830 views
Consider the following binary relations on the naturals (non-negative integers). Which ones are reflexive? Symmetric? Anti-symmetric? Transitive? Partial orders? Justify ...
1 1 vote
1 1 answer
617
617 views
The relation $\mathcal{R}$ on $\mathbb{Q}$ with $\forall x, y \in \mathbb{Q}: x \sim y$ if $x y=0$.The relation "has the same mother" on the set of students.The relation ...
1 1 vote
1 1 answer
616
616 views
Are the following relations reflexive, symmetric, transitive, antisymmetric? Explain.Let $R$ be a relation on $\mathbb{Z}$ such that $(a, b) \in R$ iff $b=a$ or $b=-a$.Le...
1 1 vote
1 1 answer
483
483 views
Let $A \neq \varnothing$ be a set. Consider the following statements:$\varnothing$ is a reflexive binary relation on $A$;$\varnothing$ is a symmetric binary relation on $...
1 1 vote
1 1 answer
713
713 views
Define the binary relation $R$ on the set $A:=\{-4,-3,-2,-1,1,2,3,4\}$ as follows:$$(x, y) \in R \Longleftrightarrow\left|x^2-y^2\right| \leqslant 5$$for all $x, y \in A$...
1 1 vote
1 1 answer
497
497 views
$$R=\left\{(x, y) \in \mathbb{N}^2: \exists n \in \mathbb{N}, x^n=y\right\}$$is a binary relation on the set of natural numbers $\mathbb{N}$.Determine which of the follow...
1 1 vote
1 1 answer
806
806 views
Determine if each of the following relations is reflexive, symmetric, antisymmetric, or transitive. Indicate if the relation is an equivalence relation.$R_1=\{(a, b) \mid...
1 1 vote
1 1 answer
665
665 views
Let $R \subseteq \mathbb{N} \times \mathbb{N}$ be a relation ( $a$ binary relation) on the set of natural numbers defined as follows:$$(x, y) \in R \Leftrightarrow x+y \g...
1 1 vote
1 1 answer
561
561 views
Among reflexive, symmetric, antisymmetric, and transitive, which of those properties are true of the above relation?It is both reflexive and symmetricIt is only reflexive...
1 1 vote
2 2 answers
754
754 views
Among reflexive, symmetric, antisymmetric, and transitive, which of those properties are true of the above relation?It is both symmetric and transitiveIt is both reflexiv...
1 1 vote
1 1 answer
650
650 views
Among reflexive, symmetric, antisymmetric, and transitive, which of those properties are true of the above relation?It is only reflexiveIt is reflexive, symmetric, and tr...
1 1 vote
1 1 answer
596
596 views
Among reflexive, symmetric, antisymmetric, and transitive, which of those properties are true of the above relation?It is only transitiveIt is both antisymmetric and tran...
1 1 vote
1 1 answer
550
550 views
Let $R$ be the relation on $M=\{1,2,3\}$ with the following diagraph representation:Then$R$ is not reflexive, not symmetric, and not transitive$R$ is transitive but not r...
2 2 votes
1 1 answer
391
391 views
Define the relation $\mathrm{O}$ on $\mathrm{Z}$ as follows:$$\forall m, n \in Z, m O n \longleftrightarrow \exists k \in Z \mid(m-n)=2 k+1$$Which one of the following st...
1 1 vote
0 0 answers
362
362 views
Given the relation $R=\{(n, m)|n, m \in \mathbb{Z}| n,|\neq| m \mid\}$. Which of the following statements about $R$ is correct?$R$ is not an equivalence relation because ...
1 1 vote
0 0 answers
313
313 views
Determine whether the following relations are reflexive, symmetric, antisymmetric, and/or transitive:The empty relation $\text{R}=\{\}$ is defined on the natural numbers....
2 2 votes
1 1 answer
418
418 views
For each of the following relations $R$ on the set of real numbers, decide whether it is reflexive, symmetric, and/or transitive? Justify your arguments. Is the relation ...
0 0 votes
1 1 answer
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 A relation '$R$ ' is defined on ordered pairs of integers as: $(x, y) R(u, v)$ if $x<u$ and $y>v$. Then $R$ isNeither a partial order nor an equivalence relationA partia...
0 0 votes
2 2 answers
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1.3k views
Identify the incorrect statement(s).A candidate key is minimal set of one or more attributes that, taken collectively, allows us to uniquely identify any entity in the en...
2 2 votes
1 1 answer
1.1k
1.1k views
Consider the two relations below. The primary keys are underlined. Identify all possible foreign key(s) from the options based only on the two relations.$\text{EMP (eid, ...