Concept

Is the empty set both an element and a subset of X?

Stephen Davies, Ph.D. Version 2.2.2 Through Discrete Mathematics A Cool Brisk Walk / Chapter 1

"X = { Q, ∅ , { Z } }. Is ∅ ∈ X ? Is ∅ ⊆ X ? Yes and yes. The empty set is an element of X because it’s one of the elements, and it’s also a subset of X because it’s a subset of every set. Hmmm."

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Is the empty set both an element and a subset of X? | Stephen Davies, Ph.D. Version 2.2.2 Through Discrete Mathematics A Cool Brisk Walk | Bifalgorithm | Bifalgorithm