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A counterexample to the triangle conjecture. (English) Zbl 0558.20032
It is known that the triangle conjecture sets a bound on the cardinality of a code formed by words of the form $$a^iba^j$$. A counterexample exceeding this bound is presented in this paper. This also disproves a stronger conjecture that every code is commutatively equivalent to a prefix code.

##### MSC:
 94A45 Prefix, length-variable, comma-free codes 05A99 Enumerative combinatorics
##### Keywords:
triangle conjecture; cardinality of a code; prefix code
Full Text:
##### References:
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