Hello everyone assume that we set $A$ = {{1 ,2} , {2 ,3} ,{4 ,3}}

so what is $\cup_{B \in A} (B)$?

$\{1,2\}\cup \{2,3\} \cup \{4,3\}$..

August 01, 2020 10:51 AM

Here The elements of $A$ are $\{1,2\}, \{2,3\}, \{4,3\}$. So the union of elements of $A$ is:

$$\cup_{B\in A} B = \{1,2\} \cup \{2,3\} \cup \{4,3\}.$$

August 01, 2020 10:56 AM

I surmise that this was a trick question. The intention is for the student to realize that the union of all elements of a specific set is the specific set itself, without any regard to what the elements actually are.

**Addendum**

Subsequent comments by Aurelio and Coward have suggested that I am mistaken. I may well be mistaken, but I'm just not seeing it yet.

Coward: In response to your comment, could you please provide a counter example?

Aurelio: In response to your counter example, perhaps I'm missing something here. In your counter example, it does seem to me that $\bigcup_{b \in A} \;=\; A.$ Please explain if you think that I am mistaken.

August 01, 2020 10:58 AM

- Serverfault Help
- Superuser Help
- Ubuntu Help
- Webapps Help
- Webmasters Help
- Programmers Help
- Dba Help
- Drupal Help
- Wordpress Help
- Magento Help
- Joomla Help
- Android Help
- Apple Help
- Game Help
- Gaming Help
- Blender Help
- Ux Help
- Cooking Help
- Photo Help
- Stats Help
- Math Help
- Diy Help
- Gis Help
- Tex Help
- Meta Help
- Electronics Help
- Stackoverflow Help
- Bitcoin Help
- Ethereum Help