Solution

ID: past-exam-of-the-year-1-of-the-computer-science-course-of-the-university-of-oxford/2022/digital-systems-linear-algebra-introduction-to-formal-proof-resit/6/c/i/solution

If with , put . The matrix geometric series telescopes on both sides:
Thus is nonsingular, and
This is a finite polynomial identity for a nilpotent matrix; no convergence argument or bound is required.

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