3fc2c97b-e4ef-460e-ae82-e878657b1288
prompter
Is the set of all invertible matrices a linear subspace of the set of all square matrices over reals?
0df9c235-2917-402f-9449-26ea39af6cc2
3fc2c97b-e4ef-460e-ae82-e878657b1288
assistant
Let's break this down:

A linear subspace means it is closed under addition, scalar multiplication, and contains the zero matrix.
The set of invertible matrices means matrices that have an inverse.
The set of all square matrices over reals just means n×n matrices with real entries.

So we need to check:

If A and B are invertible matrices, is A + B invertible? Yes, (A + B)^-1 = A^-1 + B^-1
If c is a real scalar and A is invertible, is cA invertible? Yes, (cA)^-1 = (1/c)A^-1
Is the 0 matrix invertible? No, 0 is not invertible.

Therefore, the set of invertible matrices is not a linear subspace of the set of all square matrices over reals. It fails the third condition of containing the zero matrix.