Asymmetric Relations Formula:
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Asymmetric relations are binary relations R on a set A where for all x and y in A, if (x,y) ∈ R, then (y,x) ∉ R. In other words, if there's a relation from x to y, there cannot be a relation from y to x.
The calculator uses the formula:
Where:
Explanation: For each pair of distinct elements (x,y) in set A, we have three choices: include (x,y) but not (y,x), include (y,x) but not (x,y), or include neither. This gives us 3 possibilities for each pair.
Details: Asymmetric relations are important in mathematics, computer science, and various applications where directional relationships matter, such as in directed graphs, preference relations, and order relations.
Tips: Enter the number of elements in set A. The calculator will compute the total number of possible asymmetric relations on that set.
Q1: What's the difference between asymmetric and antisymmetric relations?
A: Asymmetric relations are a subset of antisymmetric relations. In asymmetric relations, if (x,y) exists, (y,x) cannot exist. In antisymmetric relations, if both (x,y) and (y,x) exist, then x must equal y.
Q2: Can a relation be both symmetric and asymmetric?
A: Only the empty relation can be both symmetric and asymmetric. Any non-empty symmetric relation cannot be asymmetric, and vice versa.
Q3: What happens when n(A) = 0?
A: When the set is empty, there is exactly 1 asymmetric relation (the empty relation itself).
Q4: Are all asymmetric relations irreflexive?
A: Yes, all asymmetric relations are irreflexive because if (x,x) existed, it would violate the asymmetry condition.
Q5: How does this relate to directed graphs?
A: Asymmetric relations correspond to directed graphs without bidirectional edges (no pairs of opposite-directed edges between the same vertices).