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Diffstat (limited to 'set-theory.html.markdown')
| -rw-r--r-- | set-theory.html.markdown | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/set-theory.html.markdown b/set-theory.html.markdown index 6be7aa00..c6e72960 100644 --- a/set-theory.html.markdown +++ b/set-theory.html.markdown @@ -41,7 +41,7 @@ The cardinality, or size, of a set is determined by the number of items in the s For example, if `S = { 1, 2, 4 }`, then `|S| = 3`. ### The Empty Set -* The empty set can be constructed in set builder notation using impossible conditions, e.g. `∅ = { x : x =/= x }`, or `∅ = { x : x ∈ N, x < 0 }`; +* The empty set can be constructed in set builder notation using impossible conditions, e.g. `∅ = { x : x ≠ x }`, or `∅ = { x : x ∈ N, x < 0 }`; * the empty set is always unique (i.e. there is one and only one empty set); * the empty set is a subset of all sets; * the cardinality of the empty set is 0, i.e. `|∅| = 0`. @@ -87,7 +87,7 @@ D = { 2x : x ∈ N } = { 0, 2, 4, 6, 8, ... } ## Special Sets ### The Power Set -* Let `A` be any set. The set that contains all possible subsets of `A` is called a "power set" and is written as `P(A)`. If the set `A` contains `n` elements, then `P(A)` contains `2^N` elements. +* Let `A` be any set. The set that contains all possible subsets of `A` is called a "power set" and is written as `P(A)`. If the set `A` contains `n` elements, then `P(A)` contains `2^n` elements. ``` P(A) = { x : x ⊆ A } |