Mutually exclusive or not?

Question

I am searching for the proper term that describes the following set of criteria:

1) A word starts with "ab" 2) A word starts with "a"

or

1) The animal is a dog 2) The animal is a canine

As you can see it is not a case of true mutual exclusion because there is only a one-way exclusion. How can this relationship be called?

Actually, there is no exclusion at all. It's rather a matter of inclusiveness. All elements in set 1) are elements in set 2). You could say rule 1) is more specific than rule 2). — oerkelens, Aug 2, 2016 at 15:38

Community · Accepted Answer · 2020-06-15 07:40:02Z

2

From the domain of mathematics, assuming 1) is A and 2) is B:

A is a proper (or strict) subset of B.

or equivalently:

B is a proper superset of A

Alternative terms are inclusion or sometimes containment of A inside B.

As an Euler diagram:

CommunityBot

1

answered Aug 2, 2016 at 16:25

Bookeater

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Also there's a useful example about the proper subset here: mathworld.wolfram.com/ProperSubset.html
– Gary
Aug 2, 2016 at 16:44

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