Describe command word in questions

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Homework Help Overview

The discussion revolves around the interpretation of the command word "describe" in mathematical questions, particularly in the context of linear algebra and Lie algebras. Participants explore what is expected when asked to describe the kernel of a homomorphism.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question the meaning of "describe" and whether it implies finding a basis for the kernel or simply identifying it. There is a discussion about the definition of the kernel and how to present it.

Discussion Status

The conversation is ongoing, with participants sharing their interpretations and seeking clarity on the expectations of the term "describe." Some guidance on definitions has been provided, but there is no consensus on the interpretation of the command word.

Contextual Notes

Participants note that the context of the question is crucial, as it relates to Lie algebras and linear algebra, which may influence the interpretation of the command word. There is also mention of the potential ambiguity when no specific context is provided.

Ted123
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"Describe" command word in questions

I always find it a bit vague when a question tells me to "Describe".

For example "Describe the kernel of [itex]\phi[/itex]". Does this just mean find it?

If you see the word "Hence" it means use the previous result.
 
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Ted123 said:
I always find it a bit vague when a question tells me to "Describe".

For example "Describe the kernel of [itex]\phi[/itex]". Does this just mean find it?

If you see the word "Hence" it means use the previous result.

What do you mean when you "find" the kernel? "Describe the kernel" suggests to me that you are meant to find a basis for the kernel, and this basis completely characterizes the kernel.

"Hence" means that the next statement follows from the previous statement. I don't see any difference between "hence," "ergo," or "therefor."
 


Well the question I'm referring to is (in the context of lie algebras but similar for linear algebra): 'describe the kernel of the canonical homomorphism [itex]\phi : \mathfrak{g} \to \mathfrak{g} / \mathfrak{h}[/itex]' defined by [itex]\phi (x)=x+\mathfrak{h}[/itex] for all [itex]x\in\mathfrak{g}[/itex] where [itex]\mathfrak{g}[/itex] is any lie algebra (vector space with some additional properties) and [itex]\mathfrak{h}[/itex] is an ideal (subspace with some additional properties) of [itex]\mathfrak{g}[/itex].

I've found that [itex]\text{Ker}( \phi ) = \mathfrak{h}[/itex] but how would I present a basis?

What I mean by finding the kernel is using the definition [itex]\{ v\in V : \phi v)=0 \}[/itex]
 
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Ted123 said:
Well the question I'm referring to is (in the context of lie algebras but similar for linear algebra): 'describe the kernel of the canonical homomorphism [itex]\phi : \mathfrak{g} \to \mathfrak{g} / \mathfrak{h}[/itex]' defined by [itex]\phi (x)=x+\mathfrak{h}[/itex] for all [itex]x\in\mathfrak{g}[/itex] where [itex]\mathfrak{g}[/itex] is any lie algebra (vector space with some additional properties) and [itex]\mathfrak{h}[/itex] is an ideal (subspace with some additional properties) of [itex]\mathfrak{g}[/itex].

I've found that [itex]\text{Ker}( \phi ) = \mathfrak{h}[/itex] but how would I present a basis?
I was thinking vector spaces when you asked the question (and there wasn't any context to let me know you weren't talking about vector spaces).
Ted123 said:
What I mean by finding the kernel is using the definition [itex]\{ v\in V : \phi v = 0 \}[/itex]
This is just the definition of the kernel, so you haven't really found anything.
 

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