Smallest number field containing pi

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Homework Help Overview

The discussion revolves around identifying the smallest number field that contains the mathematical constant pi and proving its countability. Participants are exploring the nature of number fields and the implications of including pi within them.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are questioning the definition of the smallest number field containing pi and how to determine its cardinality. There is a suggestion to construct the field and explore its properties, including the need for it to be infinite and contain certain elements.

Discussion Status

The discussion is ongoing, with participants actively questioning the nature of the field and proposing elements that must be included. Some guidance has been offered regarding the construction of the field, but there is no consensus on the exact form it should take.

Contextual Notes

Participants note the requirement that the field must include the rational numbers and pi, and there is an emphasis on the necessity of including additional elements like pi squared to ensure closure under multiplication.

kingwinner
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1) Let F be the smallest number field containing pi. Prove that F is countable.

The first trouble I am facing is: What actually is the smallest number field containing pi? How can we know its cardnality?

Could someone please help me? Thanks!
 
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First show the field must be infinite. Then the smallest it can be is countable. To show it's countable try to construct it.
 
But what is the field?

e.g. the smallest number field is the set of rational numbers

What is the smallest number field containing pi? How can we find the cardnality without knowing what it is?
 
Last edited:
kingwinner said:
But what is the field?

e.g. the smallest number field is the set of rational numbers

What is the smallest number field containing pi? How can we find the cardnality without knowing what it is?

I told you. YOU have to construct it. You can't look it up in a table of fields. It has to contain Q and it has to contain pi. What else does it have to contain give that it contains Q and pi?
 
Is it a+b*pi, a,b E Q?
 
kingwinner said:
Is it a+b*pi, a,b E Q?

That's a good start. Now you can add and subtract. But you have to be able to multiply in the field as well. So it had better contain pi^2, right? Better keep expanding the field.
 

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