What does max{x,y} mean in discrete mathematics?

[bkc82]

I didn't really know where to put this so, I put it here. Anyway in discreet mathematics what does the term max{x,y} mean? I can't find it in the book anywhere and the problem I'm trying to do says:

max{x,y} = (x+y+|x-y|)/2 for all real x,y

Note: I'm not asking you to do the problem I just want to know what max means.

 

[Hurkyl]

If S is a set, then max S is simply the maximum element of S.

More precisely, max S = x iff:
x is in S
for all y in S: y <= x.


Note that max S is not always defined if S is an infinite set.

 

[bkc82]

Thanks I appreciate it.

 

[mathman]

The word for the mathematics you are talking about is spelled "discrete". The word "discreet" has to do with social behavior. For example if someone is dressed like a slob, it is discreet not to mention it in public.

 

[HallsofIvy]

No, mathman the word is "discrete" in either sense. There is no (English) word spelled "discreet".

 

[Muzza]

There is no (English) word spelled "discreet".

http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=discreet&x=0&y=0

 

[gazzo]

and in my little oxford lol. prudent; cautions in speech or action; unobtrusive.

 

[HallsofIvy]

What? ME- Wrong?? How can this be allowed to happen! I'm going to call Brittanica immediately and insist that they change the spelling!