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   Decomposing Projection Operators
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   Author  Topic: Decomposing Projection Operators  (Read 795 times)
JocK
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Decomposing Projection Operators  
« on: Jan 28th, 2006, 6:25am »
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Consider two non-commuting projection operators P and Q on a finite-dimensional inner-product space (i.e. two operators which are idempotent P2 = P, Q2 = Q and for which PQ =/= QP). Prove that it is not possible to construct non-negative operators R00, R01, R10, R11 (i.e. Hermitean operator with non-negative eigenvalues) such that:
 
R00 + R01 = P
 
R10 + R11 = I - P
 
R00 + R10 = Q
 
R01 + R11 = I - Q
 
(I is the identity operator).
 
« Last Edit: Jan 28th, 2006, 6:43am by JocK » IP Logged

solving abstract problems is like sex: it may occasionally have some practical use, but that is not why we do it.

xy - y = x5 - y4 - y3 = 20; x>0, y>0.
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