# Proving Richardson's theorem for constants

(I asked this a little over 3 months ago on math.SE, and when I initially re-asked here, no one had responded there. $\:$ After I re-asked here, Eric Towers responded there, since I had forgotten to give a link to here. $\:$ However, his response uses a construction whose expressions are not constants.)

Richardson's theorem is given in this wikipedia article. $\:$ In this answer, Eric Towers states that

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How can the last bullet point of that quote be proven?

• If that last comment means "there is no procedure to decide equality of variable-free expressions in the language $(1,+,-,*,/,\exp,\sin)$", then I think it's unproven. – Matt F. Feb 8 at 17:26