Not only is the symbol daunting, but the words are too

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SUMMARY

The discussion centers on verifying that the set \mathbb{F}_2 = {0, 1} is a field by checking its properties. Participants emphasize the importance of demonstrating the axioms A1 to A4 and M1 to M4, which define field operations, including closure, identity elements, and inverses. The term "curious field" refers to \mathbb{F}_2 being the smallest field, where operations like 1 + 1 = 0 illustrate unique characteristics of binary arithmetic. The conversation highlights the necessity of understanding these properties to confirm that \mathbb{F}_2 meets the criteria for a field.

PREREQUISITES
  • Understanding of field theory and its axioms (A1 to A4, M1 to M4).
  • Familiarity with binary operations and their properties.
  • Knowledge of additive and multiplicative identities in algebra.
  • Basic concepts of closure and inverses in mathematical structures.
NEXT STEPS
  • Study the properties of finite fields, particularly \mathbb{F}_p for prime p.
  • Learn how to construct addition and multiplication tables for small fields.
  • Explore the implications of closure under addition and multiplication in field theory.
  • Investigate the concept of additive and multiplicative inverses in various fields.
USEFUL FOR

Mathematics students, educators, and anyone interested in abstract algebra, particularly those studying field theory and its applications in various mathematical contexts.

  • #31
flyingpig said:
2.46 and 2.47? I had my doubts...

What in Earth do you mean with 2.46 and 2.47?
 
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  • #32
micromass said:
What in Earth do you mean with 2.46 and 2.47?

[PLAIN]http://img707.imageshack.us/img707/652/unledfz.jpg

Sorry lol, I was reading in my mind.
 
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  • #33
And how would you evaluate

1 + (0 + 1)

using those rules?
 
  • #34
1 + (0 + 1) = 1 + 1 = 0
 
  • #35
And how would you evaluate (1+0)+1 ?? Is it also 1??
 
  • #36
micromass said:
And how would you evaluate (1+0)+1 ?? Is it also 1??

(1 + 0) = 1 from 2.46

so I get 1 + 1 = 0 still

Also RedBelly I was actualyl going to post my answers lol and then it said "Sorry! the thread is locked!"

Flyingpig to Redbelly (unrelated to this thread) said:
Never mind d) is 375. They all move up by 75...each. Stupid question.

This was solutiuon they gave me

[PLAIN]http://img849.imageshack.us/img849/4906/unledhsb.png

Which just means the answer is a multiple of 5, I thought they meant the contours are "5M units apart"
 
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  • #37
OK, so that is indeed correct. We indeed have that

1 + (0 + 1) = (1 + 0) + 1 = 0

But that is not were the error was. The error is in the following

1 + (1 + 0) = (1 + 1) + 0 = 1 + 0 = 1

So can you calculate

1+(1+0)=...
(1+1)+0=...

again and see where the error is?
 
  • #38
micromass said:
So can you calculate

1+(1+0)=...
(1+1)+0=...

again and see where the error is?

But they all arrive at the same answer

1 + (1 + 0) = 1 + 1 = 0

(1 + 1) + 0 = 0 + 0 = 0

But 1 + (1 + 0) from A2 says 1 + (1 + 0) = (1 + 1) + 0 = 0 + 0

I don't see the error
 
  • #39
flyingpig said:
But they all arrive at the same answer

1 + (1 + 0) = 1 + 1 = 0

(1 + 1) + 0 = 0 + 0 = 0

But 1 + (1 + 0) from A2 says 1 + (1 + 0) = (1 + 1) + 0 = 0 + 0

I don't see the error

Indeed, they are all 0. But before you said that it was equal to 1. So now you have the correct answer.
 
  • #40
Impossible I had 0! It was in post#29!

Oh well at least I got the other 7 right! ahahhaah

Wait, does that mean I will have 8 x 8 = 64 lines to write for all the other ones...?
 
  • #41
Correction * 64
 
  • #42
Yes, now try to do the other ones. This should be quite easy if you understood this one.
 
  • #43
oH MY GOD, Please stay with me in case I made a silly mistake. With 64, I will...
 
  • #44
A1 done, A2 speaks for itself.

A2 said:
x + y = y + x

Let x = 0, y = 0

0 + 0 = 0 + 0 = 0

Let x = 0, y = 1

0 + 1 = 1 + 0 = 1

Let x = 1, y = 0

1 + 0 = 0 + 1 = 1

Let x = 1, y = 1

1 + 1 = 1 + 1 = 0

OKay probably not 64 then

A3 said:
I sense danger from this one...

x + 0 = x

Let x = 0

0 + 0 = 0

Let x = 1[/tex]

1 + 0 = 1



A4 said:
x + (-x) = 0

Oh boy

Let x = 0

0 + (-0) = 0 + 0 = 0

Let x = 1

1 + (-1) =...

Stuck already...I am an idiot

DOing M1-M4 D in another post.
 
  • #45
OK, for A4, you need to use that -1=1 and -0=0. You define this to be so.
 
  • #46
M1 said:
Damn it, 8 cases again

(xy)z = x(yz)

Let x = 0, y = 0, z = 0

(0*0)0 = 0(0*0) = 0*0 = 0

Let x = 0, y = 0, z = 1

(0*0)1 = 0(0*1) = 0*0 = 1

Let x = 0, y = 1, z = 0

(0*1)0 = 0(1*0) = 0*0 = 0

Let x = 1, y = 0, z = 0

(1*0)*0 = 1(0*0) = 1*0 = 0

Let x = 1, y = 1, z = 0

(1*1)0 = 1(1*0) = 1*0 = 0

Let x = 1, y = 0, z = 1

(1*0)1 = 1(0*1) = 1*0 = 0

Let x = 0, y =1, z = 1

(0*1)1 = 0(1*1) = 0*1 = 0


Let x = 1, y = 1, z = 1

(1*1)1 = 1(1*1) = 1*1 = 1

M2 said:
xy = yx

Let x = 0, y = 0

0*0 = 0*0 = 0

Let x = 0, y = 1

0*1 = 1*0 = 0

Let x = 1, y = 0

1*0 = 0*1 = 0

Let x = 1, y = 1

1*1 = 1*1 = 1

M3 said:
Other than 0, there is a 1 such that x * 1 = x

Let x = 0

0 * 1 = 0

Let x = 1

1*1 = 1

M4 said:
Other than 0, we have an inverse for x

Oh wait...should I just do x = 1 case...?

D said:
NOOO ANOTHER 8 CASE. I'll be back on this one...

Need water...be back in 2 mins.
 
  • #47
The second of M1 is incorrect.
 
  • #48
Yes because 0*0 is not 1...!

D said:
Let x = 0, y = 0, z = 0

0(0 + 0) = 0*0 + 0*0 = 0 + 0 = 0

Let x = 0, y = 0, z = 1

0(0 + 1) = 0*0 + 0*1 = 0 + 0 = 0

Let x = 0, y =1, z = 0

0(1 + 0) = 0*1 + 0*0 = 0 + 0 = 0

Let x = 1, y = 0, z = 0

1(0 + 0) = 1*0 + 1*0 = 0 + 0 = 0

Let x = 1, y = 1, z = 0

1(1 + 0) 1*1 + 1*0 = 1 + 0 = 1

Let x = 1, y = 0, z = 1

1(0 + 1) = 1*0 + 1*1 = 0 + 1 = 1

Let x = 0, y = 1, z = 1

0(1 + 1) = 0*1 + 0*1 = 0 + 0 = 0

Let x = 1, y = 1, z = 1

1(1 + 1) = 1*1 + 1*1 = 1 + 1 = 0

I am pretty confident in this one
 
  • #49
Looks ok!
 
  • #50
Now just imagine I have to put all of this on paper.
 
  • #51
SammyS said:
For this field, -1 = 1 . This is because the thing you need to add to 1 to give you the identity element for addition is 1.

micromass said:
OK, for A4, you need to use that -1=1 and -0=0. You define this to be so.

I overlooked something. since WHEN DID I DEFINE -1 = 1?
 
  • #52
Well, you need to find for each x, an element y such that

x+y=0

By definition, this element is -x.

So, for x=0, you need an element such that 0+y=0. When you look at the axioms, you see that y=0 is the only possibility. So -0=0.

Now, what is -1?
 
  • #53
Oh is it from 1 + 1 = 0, that 1 = -1? oh okay
 
  • #54
flyingpig said:
Oh is it from 1 + 1 = 0, that 1 = -1? oh okay

Yes.
 
  • #55
I am still stuck on M4...
 
  • #56
Take x in your field. How would you define x^{-1}??
 
  • #57
xx^{-1} = 1

x^{-1} = 1/x

That doesn't change the original definition...

I still can't use 0.
 
  • #58
Oh wait, M4 actually states for all x in R, without 0, the axiom holds, I don't even need to test x = 0 right?

Ah shoot for M3, I put 0 * 1 = 0, that's wrong isn't it? Because it says x without 0
 
  • #59
Sigh...

For each x nonzero, you need to find a y such that xy=1.
If x=1. What can you take as y?
 
  • #60
flyingpig said:
Oh wait, M4 actually states for all x in R, without 0, the axiom holds, I don't even need to test x = 0 right?

Right.
 

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