engleski

On the rules for the elimination of the non-canonical trees

The concept of Morgan tree [1] is shown to be useful in generation of all non-isomorphic trees. Namely, to each tree one can assign canonical Morgan tree. Since, the number of Morgan trees [2-3] is much larger then number of canonical Morgan trees, it is of interest to create an efficient algorithm that creates only a fraction of Morgan trees not eliminating the single canonical Morgan tree. Then, in the second step, non-canonical trees are eliminated. The rules for the recognition of non-canonical trees are proposed in [4-5]. However, it seems that Rule 3 in [4] and Rule 1se in paper [5] are not correct. In this paper, we present the counter-examples to these rules.

canonical trees; elimination rules

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