# Homework Help: How to transforn words into math in this proof

1. Nov 28, 2008

### transgalactic

i am given group A which its maximum is 5

b={-a;a of group A}
prove that the minimum of b is -5
??

i know that in group b we switch the sign of the members of group "a"

the biggest member in group "a" is the minimum of group "b"

so the minimum of "b" must be -5

how to transform this into math??

2. Nov 28, 2008

### tiny-tim

Hi transgalactic!

(i assume it's an ordered group)

-5 is a member of B.

Let c be any other member of B.

Then … ?

3. Nov 29, 2008

### transgalactic

then 5 is a member of "a"

??

Last edited: Nov 29, 2008
4. Nov 29, 2008

### tiny-tim

But what can you say about c?

5. Nov 29, 2008

### transgalactic

in group B
C>-5

??

Last edited: Nov 29, 2008
6. Nov 29, 2008

### tiny-tim

(did the forum go off-line for a time, or was that just my computer? )

Yes (or maybe ≥) … so you can write:

for any c ε B, c ≥ -5 …

and that is the way you "transform this into math", as you were asking for!

7. Nov 29, 2008

### transgalactic

how it proves that the minimum of group B is C ??