[FOM] Avoiding patterns/RCA/WKL

pax0 at seznam.cz pax0 at seznam.cz
Mon Nov 12 15:08:02 EST 2012

It is well-known that there is an infinite word not containing a square (avoiding the pattern xx)
over the three letter alphabet {0,1,2}.
My question is: Do we need WKL over RCA for this result?
The intuition is that there is a finitely branching tree of square-free prefixes in which we have to find an infinite branch.
But is WKL really used here?
Thank you, Jan Pax

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