Base Pi Integers: Isomorphism with Rationals?

  • Context: Undergrad 
  • Thread starter Thread starter Atran
  • Start date Start date
  • Tags Tags
    Base Integers Pi
Click For Summary

Discussion Overview

The discussion revolves around the concept of expressing numbers in a base defined by the irrational number \(\pi\), denoted as \(Z_{\pi}\). Participants explore whether this set can be considered a group under addition and whether it is isomorphic to the set of rational integers. The conversation includes technical reasoning, challenges to definitions, and clarifications regarding the properties of the proposed structure.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants define \(Z_{\pi}\) as the set of numbers expressed in terms of \(\pi\) in a manner analogous to decimal integers, suggesting it is countable and ordered.
  • Others question how specific numbers, such as \(11\) and \(5 + 5\), are represented in \(Z_{\pi}\) and whether they belong to the set.
  • There are claims that if \(1\) is in the group, then \(11\) must also be in it, raising concerns about closure under addition.
  • Some participants argue that the addition defined in \(Z_{\pi}\) does not align with standard addition in the reals, suggesting it does not form an interesting group structure.
  • Confusion arises regarding the interpretation of symbols like \(1\) and \(5\) as either integers or elements of the defined structure, leading to further debate about the validity of the group's properties.
  • Participants express skepticism about the utility of using \(\pi\) in this context, suggesting it complicates a representation of integers without adding meaningful insight.
  • Some participants propose that the structure resembles polynomials in one variable over the integers, while others challenge this characterization based on the definitions provided.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether \(Z_{\pi}\) forms a group or is isomorphic to the rational integers. There are competing views on the validity of the definitions and operations proposed, with significant disagreement about the implications of addition within this framework.

Contextual Notes

There are unresolved questions regarding the definitions of addition and the representation of numbers in \(Z_{\pi}\). Participants highlight potential limitations in the proposed structure, including the treatment of irrational numbers and the implications of closure under addition.

  • #31
I think maybe you want the 1's place the be the ##\frac{\pi}{10}##'s place?
 
Physics news on Phys.org
  • #32
Jarvis323 said:
I think maybe you want the 1's place the be the ##\frac{\pi}{10}##'s place?
If that's true then the 100s place should be ##10\pi##, not ##\pi^2##. But then the set is just the integers scaled by ##\pi/10## which again is not interesting.
 
  • Like
Likes   Reactions: jbriggs444
  • #33
The OP seems to have bailed from this thread. It's probably not useful to try and figure out what he really meant. (Is π = 10?)
 
  • #34
Atran said:
A proper number is expressed in \pi in a similar way as a decimal integer is expressed in base 2. For example, 4375_{\pi} = 4{\pi^3}+3{\pi^2}+7{\pi}+5.
@Atran, I don't believe you understand how numbers can be represented in different bases.
In base 2, the digits are 0 and 1. Counting would proceed from 0, 1, 10, 11, 100, 101, 110, and so on, with all numbers in this list being in binary, and corresponding to the decimal number 0, 1, 2, 3, 4, 5, 6, and so on.
In base 3, the digits are 0, 1, and 2. Any integer could be represented as a sum of multiples (0, 1, or 2) powers of 3. For example, the decimal number 34 (= 27 + 6 + 1) would be written in base-3 (ternary or trinary) as 121 (## 1 \cdot 3^3 + 2 \cdot 3^1 + 1 \cdot 3^0##).
Conversion to any other positive integer base of 2 or larger would be similar.
Atran said:
The only exception I make is that the 10 digits are included when expressing a number with \pi. To clarify, the first positive such numbers are: 0,1,2,3,4,5,6,7,8,9,{\pi},{\pi}+1,{\pi}+2,...,2{\pi},2{\pi}+1,...5{\pi},5{\pi}+1,5{\pi}+2,...,9{\pi}+8,9{\pi}+9,{\pi}^2,....
This makes no sense whatsoever. In any usual number base, such as base-2, base-3, base-8, base-10, base-16, base-64, the digits used run from 0 up to, but not including, the base. In your list, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ##\pi##, your "base" lies between 3 and 4.
A major flaw in your list is that for ##10_\pi##, or ##1 \cdot \pi^1 + 0 \cdot \pi^0##, you list this as being larger than 9. In fact, as already mentioned, it lies between 3 and 4.

Thread closed.
 

Similar threads

  • · Replies 26 ·
Replies
26
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
727
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K