Classifying Finite Abelian Groups

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Homework Help Overview

The problem involves classifying the different isomorphism classes of finite abelian groups of order 1800, with a focus on justifying the classification without listing each group individually.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the classification theorem for finitely generated abelian groups and begins with the group Z_1800. They express uncertainty about counting all possibilities. Some participants suggest listing groups individually as a way to stimulate ideas for counting. Another participant notes a conflict between the classification theorem and the Sylow theorems regarding subgroup orders, questioning how to reconcile these approaches.

Discussion Status

The discussion is exploring different methods for classifying abelian groups, with some participants emphasizing the sufficiency of the classification theorem while others express concerns about subgroup structures. There is no explicit consensus, but guidance has been offered regarding reliance on the classification theorem.

Contextual Notes

Participants are navigating the implications of the Sylow theorems and the classification theorem, with specific attention to the necessary subgroups of orders 8, 9, and 25. There is an acknowledgment of potential discrepancies in subgroup counts.

Kalinka35
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Homework Statement


Count and describe the different isomorphism classes of abelian groups of order 1800. I don't need to list the group individually, but I need to give some sort of justification.

Homework Equations


The Attempt at a Solution


I'm using the theorem to classify finitely generated abelian groups,
As always we will have Z_1800 to begin with.
Also we know 1800=23(32)(52).

But how do I count all of the possibilities?
 
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Why don't you start listing them individually? Maybe that will jog your imagination enough to figure out how to count them without listing them.
 
I've counted all the ones that you get by using the classification theorem for finite abelian groups but a problem I've encountered is using the information given by the Sylow theorems as none of the groups from the first theorem contain the necessary subgroups.
What I've gathered is that there must be at least one subgroup of order 8, 9, and 25 and there a bunch of possibilities for how many for all of them. The numbers just don't really add up right. Any ideas how to approach this?
 
You don't need the Sylow theorems. You have a complete classification theorem for abelian groups. That's all you need. That certainly gives you subgroups of order 8, 9 and 25. And several other orders besides. I'm not sure what you are fretting about. Which structure from the classification theorem doesn't give you these?
 

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