Injective Affine Linear Map for (Z/2Z)^3 to (Z/2Z)^3 Sending (1,1,1) to (0,0,0)

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Homework Help Overview

The discussion revolves around finding an injective affine linear map from (Z/2Z)³ to (Z/2Z)³ that maps the vector (1,1,1) to (0,0,0). Participants are exploring concepts related to bit permutations, circular shifts, and the properties of linear maps in modular arithmetic.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • One participant attempts to clarify the number of bit permutations and circular shifts for the set {0,1}ⁿ, questioning the implications of these definitions. Another participant discusses the criteria for an affine map to be injective and considers the determinant of the transformation matrix A.

Discussion Status

The discussion is ongoing, with participants seeking clarification and input on their reasoning. Some guidance has been offered regarding the properties of the matrix A and the conditions for injectivity, but no consensus has been reached on the correctness of the approaches presented.

Contextual Notes

Participants are working under time constraints, as there is a deadline for submission. There are also references to specific criteria for bijections and injective mappings that are being debated.

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What is the number of bit permutations of the set {0,1}n and the number of circular right shifts of the set {0,1}n.

I think the number of bit permuations is 2n, so is there 4 bit permutations here? Namely (0,0), (0,1), (1,0) and (1,1).

And the right shift is just sending each element one space right isn't it?

i.e. (0,0) -> (0,0) , (0,1) -> (1,0) etc

So what does he mean by the number of shifts? 4?

Find an injective affine linear map (Z/2Z)3 -> (Z/2Z)3 that sends (1,1,1) to (0,0,0).

In my notes all I have is that

f(v) = Av + b

Here I'm trying to find A, with given v = (1,1,1) and f(v) = (0,0,0)

I also have that for this to be a bijection

=> for (Z/mZ)n -> (Z/mZ)l then n=l and gcd(det(A), m) = 1

So since this is needed for a bijection am I ok in saying this can be the criteria for it to be injective?

So if I find an A where (det(A), 2) = 1 , => det(A) can equal 1

i.e. A =

0 1 0
0 0 1
1 0 0

and so Av = (1,1,1) and now I can take b = (1,1,1) so that Av+b = (2,2,2) = (0,0,0)?

Is this all correct? Thanks.
 
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I don't have long until I have to hand this in, would be nice for some input (any at all)!
 
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last bump i spose
 

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