Partition of Integers with mod

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    Integers Partition
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Homework Help Overview

The discussion revolves around whether specific subsets of integers form a partition of the set of integers, particularly focusing on integers divisible by 4 and those equivalent to 1, 2, or 3 mod 4.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the definition of a partition and provide examples using integer division and remainders. Questions arise regarding how negative integers fit into the proposed partition.

Discussion Status

Some participants express confidence in the partitioning argument, while others seek clarification on terminology and the need for formal proof. There is a mix of informal reasoning and attempts to understand the requirements for a formal proof.

Contextual Notes

Participants note that the discussion is not intended to be a formal proof and question whether a simple affirmative or negative response suffices for the homework requirement.

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Homework Statement


Are the following subsets partitions of the set of integers?

The set of integers divisible by 4, the set of integers equivalent to 1 mod 4, 2 mod 4, and 3 mod 4.


Homework Equations





The Attempt at a Solution


Yes, it is a partition of the set of integers. Consider 4/4 = 1, 5/4 = 1 R 1, 6/4 = 1 R 2, 7/4 = 1 R 3.

However, how would you create a negative number like -5?
 
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nicnicman said:

Homework Statement


Are the following subsets partitions of the set of integers?

The set of integers divisible by 4, the set of integers equivalent to 1 mod 4, 2 mod 4, and 3 mod 4.

Homework Equations


The Attempt at a Solution


Yes, it is a partition of the set of integers. Consider 4/4 = 1, 5/4 = 1 R 1, 6/4 = 1 R 2, 7/4 = 1 R 3.

However, how would you create a negative number like -5?

I'm not too clear on what your argument is supposed to mean. What's R? But -5=3 mod 4 since (-5)=(-2)*4+3. Hmm, I think I see. R means 'remainder', yes?
 
Last edited:
Sorry, I forgot to mention this is far from a formal proof. R just means remainder.
 
nicnicman said:
Sorry, I forgot to mention this is far from a formal proof. R just means remainder.

Yeah, it is far from formal. But I see what you are doing. Are you supposed to give something formal or just answer yes or no?
 
Just answer yes or no. And, you answered my question. I'm pretty sure the answer is yes. Thanks.
 

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