Hello, terr13!

So far, I havetwoof the examples . . .

What are naturally occuring examples of relations that satisfy two of the

following properties, but not the third: Reflexive, Symmetric, and Transitive?

Let = "is a brother of"

. . (The first is male, and both parties are children of the same parents.)

Reflexive: .

. .

Symmetric: .

. .

Not necessarily true . . .

Transitive: .

. .

The relationship is reflective and transitive, but not symmetric.

Let = "knows" (is acquainted with).

Reflexive: .

. . .True.

Symmetric: .

. . .True

Transitive: .

. . .not necessarily true

The relationship is reflexive and symmetric, but not transitive.