Prove the Identity by Using a Sign Reversing Involution (See Attachment)
I am not seeing an attachment.
Is this homework or a question from a textbook??
The attachment is there now, and no, it's not a homework question. I'm just trying to understand the involution and I wasn't sure where to post it as I haven't been on here in YEARS. Apologies if it is in the incorrect location.
I'll move it to homework, since it seems to be a textbook-type problem.
So what did you try to solve the problem? Where are you stuck?
Pretty much at the beginning, I'm not even entirely sure how to approach the identity.
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