Linear Algebra - Infinite fields and vector spaces with infinite vectors

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SUMMARY

The discussion focuses on proving that a nontrivial vector space V over an infinite field F contains infinitely many vectors. The key argument presented is that since F is infinite, there are infinitely many scalars available to apply to a non-zero vector v in V. The proof establishes that for any two distinct scalars a1 and a2 in F, the vectors a1v and a2v are distinct, confirming the existence of infinitely many vectors in V.

PREREQUISITES
  • Understanding of infinite fields, specifically the properties of fields with infinite elements.
  • Knowledge of vector spaces and their axioms.
  • Familiarity with scalar multiplication in vector spaces.
  • Basic proof techniques in linear algebra.
NEXT STEPS
  • Study the properties of infinite fields in more depth.
  • Explore the axioms and definitions of vector spaces in linear algebra.
  • Learn about scalar multiplication and its implications in vector spaces.
  • Investigate proof techniques commonly used in linear algebra, such as contradiction and direct proof.
USEFUL FOR

Students of linear algebra, mathematicians interested in vector space theory, and educators teaching concepts related to infinite fields and vector spaces.

corey115
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Homework Statement


Let F be an infinite field (that is, a field with an infinite number of elements) and let V be a nontrivial vector space over F. Prove that V contains infinitely many vectors.


Homework Equations


The axioms for fields and vector spaces.


The Attempt at a Solution


I'm thinking this is easier than I'm making it. Can I say, at the very least, F is countably infinite, so then there exist an infinite amount of scalars to apply to V?
 
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Yes, it really is that easy. Since V is a non-trivial vector space it contains a non-zero vector, v. And then for any a in F, av is in V. The "non-trivial" part of the proof is showing that if [itex]a_1\ne a_2[/itex] then [itex]a_1v\ne a_2v[/itex] but that is easy to show.
 

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