<table>
<thead>
<tr>
<th>記号</th>
<th>説明</th>
</tr>
</thead>
<tbody>
<tr>
<td>o ∈ A</td>
<td>o is a member (or element) of A</td>
</tr>
<tr>
<td>A ⊆ B</td>
<td>If all the members of set A are also members of set B, then A is a subset of B</td>
</tr>
<tr>
<td>A ∪ B</td>
<td>
<strong>Union of the sets A and B</strong> is the set of all objects that are a member of A, or B, or both.</td>
</tr>
<tr>
<td>A ∩ B</td>
<td>
<strong>Intersection of the sets A and B</strong> is the set of all objects that are members of both A and B.</td>
</tr>
<tr>
<td>U \ A</td>
<td>
<strong>Set difference of U and A</strong> is the set of all members of U that are not members of A.</td>
</tr>
</tbody>
</table>
<p>ここから -&gt; <a href="https://en.wikipedia.org/wiki/Set_theory" target="_blank" rel="nofollow noopener noreferrer">https://en.wikipedia.org/wiki/Set_theory</a></p>


Set theoryの記号

Discussion

記号	説明
o ∈ A	o is a member (or element) of A
A ⊆ B	If all the members of set A are also members of set B, then A is a subset of B
A ∪ B	Union of the sets A and B is the set of all objects that are a member of A, or B, or both.
A ∩ B	Intersection of the sets A and B is the set of all objects that are members of both A and B.
U \ A	Set difference of U and A is the set of all members of U that are not members of A.