Linear Algebra - 12 - Subspaces

What is a subspace? What makes a space a subspace of a given vector space? How is the span of a vector set related to a subspace?

[khtiderem]

these are really helpful videos and I don't understand how more people haven't watched

[PhysicsMath]

These guys are those.who hold the sky so its doesn't fall on my head..

[alfredolim]

your videos are informative, please keep it up

[maxpercer]

you definitely know how to simplify subjects ;o

[martingeorgiev]

I think that a subspace A could be equal to the parent space.