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On almost invariant subspaces for implicit linear discrete-time systems. (English) Zbl 0666.93052
The concept of almost invariant subspace for an implicit linear discrete- time system is introduced and studied in detail. It is shown also that for regular homogeneous implicit systems the so-called deflating subspaces can be identified with almost invariant subspaces.

##### MSC:
 93C05 Linear systems in control theory 93C55 Discrete-time control/observation systems 47A15 Invariant subspaces of linear operators 34A99 General theory for ordinary differential equations 39A12 Discrete version of topics in analysis
##### Keywords:
almost invariant subspace; deflating subspaces
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##### References:
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