Question 578689
How does one show that an operator is invertible?
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Let's say "a" is your operator.
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You want it to operate on "b"
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It gives you "c" as a result.
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Now assume you have an operator "d"
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You want it to operate on "c" and it gives you "a".
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Do you see that "d" has undone what "b" did?
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That means "b" and "d" are inverse operators.
It also shows that "b" is invertible: it can be undone.
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Dressing and undressing are invertible.
Eating is not invertible.
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Cheers,
Stan H.