Whats the meaning of Parallel in Vectors

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    Parallel Vectors
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Discussion Overview

The discussion revolves around the definition of parallel vectors, particularly in the context of vector relationships and their mathematical implications. Participants explore various interpretations of what it means for vectors to be parallel, including conditions involving scalar multiplication and the implications of different metrics.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes that if ##\vec u = c\vec r## where c is a real constant, then ##\vec u## and ##\vec r## can be considered parallel, questioning the definition of parallelism when c is negative.
  • Another participant suggests that the concept of parallelism is fundamentally a matter of definition rather than proof.
  • A further contribution emphasizes the need for a solid reference or definition from accepted texts to support the understanding of parallel vectors.
  • One participant defines parallel vectors in terms of parallel lines, which are characterized by maintaining a constant distance, but notes that the definition of distance is not universally agreed upon.
  • Another participant challenges the notion of distance and parallelism, indicating that the metric used can influence the definition of parallel vectors.
  • A specific example is provided with vectors ##\vec u=(1,0,0)## and ##\vec r=(-1,0,0)##, questioning their parallelism in Euclidean space.
  • It is noted that parallelism can be defined in different ways, such as by constant distance or constant distance greater than zero, leading to differing conclusions about whether certain vectors are parallel.

Areas of Agreement / Disagreement

Participants express differing views on the definition of parallel vectors, with no consensus reached on a universally accepted definition or the implications of negative scalar multiplication on parallelism.

Contextual Notes

The discussion highlights the lack of a universally valid concept of distance in defining parallelism, indicating that the definitions may depend on the chosen metric.

Arman777
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Lets suppose we have a two vectors where ##\vec u=c\vec r## where c is just a reel constant number.Can we say ##\vec u## and ##\vec r## is parallel.

How can we define ""parallel" vectors ? Like in most general way.

I know that when c is positive real number they are definitely parallel.But when c is negative still can we call them "parallel".I am thinking yes we can but I need some solid proof

Thanks
 
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Proof? It is a matter of definition ...
 
Orodruin said:
Proof? It is a matter of definition ...
Solid proof of definition.I don't even know that make sense or not but I mean like a definition comes from some general acceptable textbook or from some article etc.Not just an idea but I can show some referance.
 
  1. parallel vectors = parallel lines, defined by these vectors
  2. parallel lines = constant distance at each point
So now, you have to define the distance between two lines. It is here, were the definition plays a role, because there is no universally valid concept of distance. That's why we speak of metrics. Tell me your metric and I will tell you parallelism.
 
fresh_42 said:
ell me your metric and I will tell you parallelism.
Metric ? I don't know ...
 
Think like this for simple case. ##\vec u=(1,0,0)## and ##\vec r=(-1,0,0)## Are these vectors parallel ?
 
In Euclidean space, yes. However, you could either define "parallel" by "constant distance", which I prefer to use, or by "constant distance greater than zero", in which case they wouldn't be parallel. After my fancy, this is an ugly condition, but Euclid probably used this distinction.
 
fresh_42 said:
In Euclidean space, yes. However, you could either define "parallel" by "constant distance", which I prefer to use, or by "constant distance greater than zero", in which case they wouldn't be parallel. After my fancy, this is an ugly condition, but Euclid probably used this distinction.
Makea sense..I don't know that much of geometry/algebra sadly.But I understand.
Thanks :)
 

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