Scalar quantities and complex numbers

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Discussion Overview

The discussion revolves around the classification of scalar quantities, specifically whether complex numbers can be considered scalars alongside real numbers. Participants explore the definitions and implications of scalars in various mathematical contexts.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants define scalars as quantities that consist of a number (positive or negative) and may include a measuring unit, providing examples such as 6, 5 kg, and -900 J.
  • One participant asserts that complex numbers are considered scalars, noting that while they can represent magnitude and direction in a 2D number plane, this plane is a mathematical construct rather than a physical one.
  • Another participant argues that scalars can include numbers, rationals, reals, complex numbers, or even quaternions, emphasizing that units are not part of scalars and that scalars are dimensionless.
  • There is a request for references or resources to further explore the topic, indicating a desire for additional context or clarification on the definitions of scalars.
  • A participant questions the context in which scalars are being discussed, asking for clarification on whether they refer to numbers, vector spaces, scalar fields, or other mathematical constructs.

Areas of Agreement / Disagreement

Participants express differing views on the classification of complex numbers as scalars, with no consensus reached on the definitions or implications of scalars in various mathematical contexts.

Contextual Notes

The discussion highlights potential ambiguities in the definitions of scalars, particularly regarding the inclusion of units and the dimensionality of the quantities involved. The context of scalar quantities may vary depending on mathematical or physical frameworks.

topito2
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I was taught a scalar is a quantity that consists of a number (positive or negative) and it might include a measuring unit, e.g. 6, 5 kg, -900 J, etc. I was wondering if complex numbers like 3 + 7j (where j is the square root of minus 1) can be considered scalar quantities too, or is it that only real numbers (that might include measuring units) can be considered scalars?
 
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Complex numbers are considered scalars. Although complex numbers can be thought of as a magnitude and direction in the 2D number plane, the number plane is a mathematical space and not a physical space like horizontal and vertical.
 
topito2 said:
I was taught a scalar is a quantity that consists of a number (positive or negative) and it might include a measuring unit, e.g. 6, 5 kg, -900 J, etc. I was wondering if complex numbers like 3 + 7j (where j is the square root of minus 1) can be considered scalar quantities too, or is it that only real numbers (that might include measuring units) can be considered scalars?
Scalars are numbers, rationals, reals, complex or even quaternions. Units are not part of them! A unit is a special measure of a dimension like length or weight. Scalars are dimensionless.
 
Thank you so much for the speedy reply, guys! BTW, could you please provide any reference (book or website) I could check to dig a little bit more on the subject?
 
topito2 said:
Thank you so much for the speedy reply, guys! BTW, could you please provide any reference (book or website) I could check to dig a little bit more on the subject?
Can you tell which direction?
Scalars as numbers? Which? Scalars as part of vector spaces or algebras? Scalar fields? Scalars as opposing vectors?
In the end they are simply numbers. Which, depends on what for. Or which role they play in certain contexts.
 

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