2023-03-05

221: Set of Vectors Space Homomorphisms Constitutes Vectors Space

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A description/proof of that set of vectors space homomorphisms constitutes vectors space

Topics


About: vectors space

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Starting Context



Target Context


  • The reader will have a description and a proof of the proposition that for any 2 vectors spaces over any same field, the set of vectors space homomorphisms constitutes a vectors space.

Orientation


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There is a list of propositions discussed so far in this site.


Main Body


1: Description


For any vectors spaces, V1,V2, over any same field, F, the set of vectors space homomorphisms, Hom(V1,V2):={f:V1V2}, is a vectors space over F with the vectors space operation defined as (r1f1+r2f2)(v)=r1f1(v)+r2f2(v) where riF, fiHom(V1,V2), and vV1.


2: Proof


r1f1(v)+r2f2(v)V2. So, r1f1+r2f2 is a map from V1 to V2. Is r1f1+r2f2 a vectors space homomorphism? For any r3,r4F and any v1,v2V1, (r1f1+r2f2)(r3v1+r4v2)=r1f1(r3v1+r4v2)+r2f2(r3v1+r4v2)=r1r3f1(v1)+r1r4f1(v2)+r2r3f2(v1)+r2r4f2(v2)=r3(r1f1(v1)+r2f2(v1))+r4(r1f1(v2)+r2f2(v2))=r3((r1f1+r2f2)(v1))+r4((r1f1+r2f2)(v2)). So, yes, r1f1+r2f2 is a vectors space homomorphism.


References


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