Doubting Logic: Boolean Matrix Homework Help

  • Thread starter Thread starter noreturn2
  • Start date Start date
  • Tags Tags
    Matrix
Click For Summary

Homework Help Overview

The discussion revolves around a homework problem related to Boolean matrices, specifically focusing on operations such as matrix multiplication and bitwise operations. Participants express doubts about their logic and the correctness of their answers, particularly regarding the results of matrix products.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants share their attempts at solving the problem, questioning the validity of their answers and the logic behind matrix multiplication in the context of Boolean values. There are discussions about the results of specific matrix products and the interpretation of operations like bitwise AND and OR.

Discussion Status

Some participants have provided feedback on each other's answers, noting discrepancies and suggesting areas for clarification. There is an ongoing exploration of how Boolean arithmetic should be applied in the context of matrix multiplication, with no clear consensus reached yet.

Contextual Notes

Participants are working under the constraints of homework rules, which may limit the information they can share. There is also a focus on understanding the definitions and operations specific to Boolean algebra, particularly regarding how values are combined in matrix calculations.

noreturn2
Messages
25
Reaction score
0

Homework Statement


FjMJidm.gif


Homework Equations

The Attempt at a Solution



media%2Fd09%2Fd09fb498-ecfe-475f-b5a1-fbc8fc68c088%2Fphp5JGkPY.png

Does my logic seem right, I'm doubtin my anwsers.
 

Attachments

  • FjMJidm.gif
    FjMJidm.gif
    25.3 KB · Views: 1,785
  • media%2Fd09%2Fd09fb498-ecfe-475f-b5a1-fbc8fc68c088%2Fphp5JGkPY.png
    media%2Fd09%2Fd09fb498-ecfe-475f-b5a1-fbc8fc68c088%2Fphp5JGkPY.png
    19.4 KB · Views: 2,066
Physics news on Phys.org
noreturn2 said:

Homework Statement


View attachment 235016

Homework Equations

The Attempt at a Solution



View attachment 235017
Does my logic seem right, I'm doubtin my anwsers.
Your answers for parts a and b seem OK, but I didn't check that closely, plus you didn't show how the bitwise AND and OR operations are supposed to work.
Your answer to c is incorrect, at least based on how matrix multiplication is normally defined. For the product CC, the upper left entry in the product matrix should be 2, not 1 as you show. This is obtained by calculating the dot product of row 1 of the left matrix with column 1 of the right matrix.
 
Boolean values can only be 1 or 0.

I think you are right that it is still wrong.

I re did it and I got:
[ 1 1 1
0 1 0
1 1 1]
 
noreturn2 said:
Boolean values can only be 1 or 0.

I think you are right that it is still wrong.

I re did it and I got:
[ 1 1 1
0 1 0
1 1 1]
I get something else. Here's what I get for ##C^2##.
##\begin{bmatrix} 1 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 0 \end{bmatrix} \begin{bmatrix} 1 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 0 \end{bmatrix}##
##= \begin{bmatrix}0 & 1 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 1 \end{bmatrix}##
The entry in the upper left corner deserves some explanation. The 0 value there is the result of the dot product of row 1 on the left (<1, 0, 1>) with col. 1 on the right (<1, 0, 1>^T). From this I get 1*1 + 0*0 + 1*1 = 2, or 102. Since this is 2 bits, it won't fit into 1 bit, we get 0 for the upper left corner of the product.
I'm assuming that's how you're supposed to be doing multiplication of Boolean values.
 
Mark44 said:
I get something else. Here's what I get for ##C^2##.
##\begin{bmatrix} 1 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 0 \end{bmatrix} \begin{bmatrix} 1 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 0 \end{bmatrix}##
##= \begin{bmatrix}0 & 1 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 1 \end{bmatrix}##
The entry in the upper left corner deserves some explanation. The 0 value there is the result of the dot product of row 1 on the left (<1, 0, 1>) with col. 1 on the right (<1, 0, 1>^T). From this I get 1*1 + 0*0 + 1*1 = 2, or 102. Since this is 2 bits, it won't fit into 1 bit, we get 0 for the upper left corner of the product.
I'm assuming that's how you're supposed to be doing multiplication of Boolean values.

Well if you have 1*1 on any column that value is autoamtically 1. So if you like at row 1 column one on each that is why I get a 1 in the corner
 
noreturn2 said:
Well if you have 1*1 on any column that value is autoamtically 1. So if you like at row 1 column one on each that is why I get a 1 in the corner
I agree that 1*1 = 1, but I was talking about 1*1 + 0*0 + 1*1 = 1 + 1 = 2.
That's how ordinary matrix multplication would be done, but you didn't include any information about how the Boolean values are to be added. For example, 0 + 0 = 0, 1 + 0 = 0 + 1 = 1, but what is 1 + 1? In terms of bits, which are essentially Boolean values, 1 + 1 = 0, with a carry of 1.
 
I do not understand how you calculated part b.
E.g. how do you get that 0 in the second column, first row?
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
1K
Replies
2
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
Replies
10
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
1
Views
903
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K