Consider the empty set as a relation, R, on any non-empty set S. Prove or disprove: R is transitive.
Let's prove with an example, let's consider a statement, if A
then B.
This is false only when A is true and B is false.
To prove that , let's consider : "if x is a human then x can eat" is not always going to be true, we need to give an example of something that is human but cannot eat.
Relation R is transitive for all x,y,z
if (x,y)∈R
and
(y,z)∈R
then (x,z)∈R.
If R is an empty relation, then (x,y)∈R and (y,z)∈R cannot be
true.
But the whole statement cannot be false.
This proves that R is transitive on any non-empty set S.
Consider the empty set as a relation, R, on any non-empty set S. Prove or disprove:...
Let P(X) be the power set of a non-empty set X. For any two subsets A and B of X, define the relation A B on P(X) to mean that A union B = 0 (the empty set). Justify your answer to each of the following? Isreflexive? Explain. Issymmetric? Explain. Istransitive? Explain.
(1) Suppose R and S are reflexive relations on a set A. Prove or disprove each of these statements. (a) RUS is reflexive. (b) Rn S is reflexive. (c) R\S is reflexive. (2) Define the equivalence relation on the set Z where a ~b if and only if a? = 62. (a) List the element(s) of 7. (b) List the element(s) of -1. (c) Describe the set of all equivalence classes.
Prove or disprove: The relation "is-a-normal-subgroup-of" is a transitive relation. (please do not solve using facts about the index)
9. Let R an equivalence relation. Prove or disprove that R:R is an equivalence relation
Let S be the set of all subsets of Z. Define a relation,∼, on S by “two subsets A and B of Z are equivalent,A∼B, if A⊆B.” Prove or disprove each of the following statements: (a)∼is reflexive(b)∼is symmetric(c)∼is transitive
Prove/disprove for any regular expressions R and S: (a) (R + S)∗S = (R∗S)∗ (b) (R + S)∗ = (R∗S)∗ Note: when disproving a statement, you must give a concrete example of R and S, meaning a definition of R and S over some chosen alphabet.
(17) (20pt) Let F be the set of functions f : R+ → R. Prove that the binary relation "f is 0(g)" on F is: (a) (4pt) Write down the definition for "f is O(g)". (b) (4pt) Prove that the relation is reflexive (c) (6pt) Prove that the relation is not symmetric. (d) (6pt) Prove that the relation is transitive. (17) (20pt) Let F be the set of functions f : R+ → R. Prove that the binary relation "f...
Let S ⊂ R be a non-empty set. For any functions f and g from S into R, define d(f,g) := sup{|f(x)−g(x)| : x∈S}. Is d always a metric on the set F of functions from S into R? Why or why not? What does your answer suggest that we do to find a (useful) subset of functions from S to R on which d is a metric, if F does not work? Give a brief justification for your fix.
Let S be a set, and R an antisymmetric relation on S. Prove that R^c is trichotomous.
probelms 9.1 9 Modular arithmetic Definition 9.1 Let S be a set. A relation R = R(,y) on S is a statement about pairs (x,y) of elements of S. For r,y ES, I is related to y notation: Ry) if R(x,y) is true. A relation Ris: Reflexive if for any I ES, R. Symmetric if for any ry ES, Ry implies y Rr. Transitive if for any r.y.ES, Ry and yRimply R. An equivalence relation is a reflexive, symmetric and...