I don't understand how if U and W are subspaces of V such that and then U + W will be S-invariant even if U and W aren't. Can someone explain this to me? I need to understand this to make an operator S for 2x2 matrices.

- March 28th 2010, 03:46 PMjiffylou[SOLVED] How can U + W be S-invariant even if U and W aren't?
I don't understand how if U and W are subspaces of V such that and then U + W will be S-invariant even if U and W aren't. Can someone explain this to me? I need to understand this to make an operator S for 2x2 matrices.

- March 28th 2010, 03:52 PMBruno J.
Well if , then .