What conditions do I need if I want to prove a relation which is both symmetric and transitive is also reflexive?
10858
Why isn't reflexivity redundant in the definition of equivalence relation?
14162
How can I prove $\sup(A+B)=\sup A+\sup B$ if $A+B=\{a+b\mid a\in A, b\in B\}$
69043
The equivalence relation generated by a relation
25155
Suppose $R$ and $S$ are transitive relations on $A$. Prove that if $S \circ R \subseteq R \circ S$ then $R \circ S$ is transitive.
79223
Doesn't symmetry and transitivity imply reflexitivity?
61538
Given a square matrix $A$, both $AA^T$ and $A^TA$ are symmetric
158355
If $A$ commutes with $B$ and $B$ commutes with $C$, then $A$ commutes with $C$
93410
How to prove ~ (~P & ~Q) : P ∨ Q by natural deduction
17935
Can a relation with less than 3 elements be considered transitive?
77337
Is an Anti-Symmetric Relation also Reflexive?
99346
Prove a result on transitive group actions.
74015
Number of relations that are both symmetric and reflexive
134588
Seeking a direct proof about nested inclusions
131596
Symmetric Inequality in $\mathbb{R}$
99911
How to show that if $x=(p,q)$ and $y=(p',q')$ then $x \sim y $ if $pq'=p'q$ is an equivalence relation?
18800
If A and B are symmetric is AB=BA true?
17363
Prove that the intersection of two equivalence relations is an equivalence relation.