Cancellation of digraphs over the direct product
نویسندگان
چکیده
منابع مشابه
Cancellation of digraphs over the direct product
In 1971 Lovász proved the following cancellation law concerning the direct product of digraphs. If A, B and C are digraphs, and C admits no homomorphism into a disjoint union of directed cycles, then A × C ∼= B × C implies A ∼= B. On the other hand, if such a homomorphism exists, then there are pairs A ≁= B for which A×C ∼= B×C . This gives exact conditions on C that governwhether cancellation ...
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ژورنال
عنوان ژورنال: European Journal of Combinatorics
سال: 2013
ISSN: 0195-6698
DOI: 10.1016/j.ejc.2012.11.003