# basis of a vector space

• Jan 18th 2014, 07:11 PM
basis of a vector space

I know that the answer is 'No'. I can justify the answer by providing two different basis of the same vector space. Is there any other way to defend the answer by giving logic and arguments.
• Jan 18th 2014, 11:17 PM
emakarov
Re: basis of a vector space
Quote:

I know that the answer is 'No'.

The correct answer depends on the vector space.
• Jan 18th 2014, 11:35 PM
Re: basis of a vector space
I think if we change the question to

Is it possible to have more than one basis of a vector space ? Justify answer

Then the correct answer will be unique.
• Jan 18th 2014, 11:45 PM
emakarov
Re: basis of a vector space
Why don't you formulate your statement precisely, using quantifiers "for all" and "there exists"? I would say that the answer to "Is it possible to have more than one basis of a vector space?" also depends on the vector space.
• Jan 19th 2014, 12:40 AM
romsek
Re: basis of a vector space
Quote:

I know that the answer is 'No'. I can justify the answer by providing two different basis of the same vector space. Is there any other way to defend the answer by giving logic and arguments.

without specifying that your basis vectors are unit (or some other) length you can always choose scalar multiple of a given basis and clearly this will also be a basis.
• Jan 19th 2014, 12:44 AM
Re: basis of a vector space
Is there exist any vector space whose basis is not unique? Justify
• Jan 19th 2014, 12:57 AM
emakarov
Re: basis of a vector space
Quote:

Originally Posted by romsek
without specifying that your basis vectors are unit (or some other) length you can always choose scalar multiple of a given basis and clearly this will also be a basis.

And yet any scalar multiple of a certain vector is equal to that original vector. That is, if there is a vector in the basis at all.

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