# Terminology clarification: ***exchanges***

I need help with a terminology definition. If we say "R is a reflection that exchanges the sides a and b in some triangle", does it mean sides a and b have the same length and the reflection maps one on the other exactly? Or does it mean something else, like swapping places (where the lengths are not necessarily equal? Though that would make the statement trivially true hence redundant...)

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The latter isn't even well-defined. I'd go with the former. – anon Feb 9 '12 at 21:33