Abstract vector spaces
What to learn
- Back to the beginning, what is vector?
Description
- Function is vector?
- Yes!
- It is another type of vector with different basis.
- example : In polynomial space, we can express
\[x^2 + 3x + 5 = \begin{bmatrix}
5\\3\\1
\end{bmatrix},b_0(x) = 1,b_1(x)=x,b_2(x) = x^2\]
- We can say all of things as vector that satisfy axiom of vector!
- Rule for vectors addition and scaling
-
\[\vec{u} + (\vec{v}+\vec{w}) = (\vec{u} + \vec{v})+\vec{w}\]
-
\[\vec{v}+\vec{w} = \vec{w}+\vec{v}\]
-
\[\vec{0} + \vec{v} = \vec{v}\]
-
\[- \vec{v} + \vec{v} = \vec{0}\]
-
\[a(b\vec{v}) = (ab)\vec{v}\]
-
\[1\vec{v} = \vec{v}\]
-
\[a(\vec{v}+\vec{w} ) = a\vec{v}+a\vec{w}\]
-
\[(a+b)\vec{v} = a\vec{v} + b\vec{v}\]
- In the modern theory the form that vectors take doesn’t really matter.
Next Step
- review! and solve a mount of problems!
References
- https://www.youtube.com/watch?v=PFDu9oVAE-g&list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab&index=15