# A?B

• Aug 15th 2012, 11:09 AM
purplesmiles
A?B
I know this is probably really simple. However, I've searched and searched online and in my book and I cannot figure out what the question mark means. I figure that it must be a substitute for another symbol since I cannot find it anywhere. Can someone tell me what the meaning of the question mark is in A?B
• Aug 15th 2012, 11:13 AM
Plato
Re: A?B
Quote:

Originally Posted by purplesmiles
I know this is probably really simple. However, I've searched and searched online and in my book and I cannot figure out what the question mark means. I figure that it must be a substitute for another symbol since I cannot find it anywhere. Can someone tell me what the meaning of the question mark is in A?B

It could mean almost anything. You saw in some context. What context? Post the entire quotation.
• Aug 15th 2012, 11:15 AM
purplesmiles
Re: A?B
The sets N; Z; Q; R are described on page 116. Show that Z ⊂ Q but Q ⊄ Z. Do you think the integers 0 and 1 are rational numbers? Explain

The above is the question that was asked. The empty boxes are where the ? are.
• Aug 15th 2012, 11:32 AM
HallsofIvy
Re: A?B
Quote:

Originally Posted by purplesmiles
The sets N; Z; Q; R are described on page 116. Show that Z ⊂ Q but Q ⊄ Z. Do you think the integers 0 and 1 are rational numbers? Explain

The above is the question that was asked. The empty boxes are where the ? are.

The empty boxes? I see subset signs! If you saw that on a website then the "?" are symbols your web browser did not recognize. You are told that Z (the set of all integers) is a subset of Q (the set of all rational numbers) but that the converse is not true. 0 and 1 are integers and question is, are they rational numbers.
• Aug 15th 2012, 11:36 AM
purplesmiles
Re: A?B
So they are subset signs? Ok that makes more sense. is there a browser that works best with these type of symbols?
• Aug 15th 2012, 12:07 PM
emakarov
Re: A?B
Quote:

Originally Posted by purplesmiles
is there a browser that works best with these type of symbols?

This depends not so much on the browser as on the font you are using. Arial Unicode MS and DejaVu Sans are two fonts that have pretty good coverage of mathematical symbols (I don't have Arial Unicode right now, but that's what I remember). In desktop Firefox, for example, you can change font in Tools | Preferences | Content.