Direct sum of vector spaces

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created: 2021-12-10 18:52:59
modified: 2022-01-16 13:48:19

If are vector spaces over a field , we will construct a new vector space called the direct sum of and . The set of vectors in is just the set of all ordered pairs with and 1. We add these pairs this way:

And for a scalar we define:

The set forms a vector space this way since and do as well.

Zero vector

The zero vector in is .

basis and dimension

As we can see in Basis of direct sum vector space, the dimension of is:


  1. So it is just an element of the Cartesian product of the vector spaces.