The work considers an equivalence relation in the set of all n x m binary matrices. In each element of the factor-set generated by this relation, we define the concept of canonicalbinarymatrix, namely the minimal el...
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The work considers an equivalence relation in the set of all n x m binary matrices. In each element of the factor-set generated by this relation, we define the concept of canonicalbinarymatrix, namely the minimal element with respect to the lexicographic order. For this purpose, the binary matrices are uniquely represented by ordered n-tuples of integers. We have found a necessary and sufficient condition for an arbitrary matrix to be canonical. This condition could be the base for realizing recursive algorithm for finding all n x m canonicalbinary matrices and consequently for finding all bipartite graphs, up to isomorphism with cardinality of each part equal to n and m. (C) 2017 Elsevier Inc. All rights reserved.
Let Lambda(k)(n) be the set of all n x n binary matrices with exactly k units in each row and each column, 1 <= k <= n. A matrix A is an element of Lambda(k)(n) will be called primitive, if there is no l x l sub...
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Let Lambda(k)(n) be the set of all n x n binary matrices with exactly k units in each row and each column, 1 <= k <= n. A matrix A is an element of Lambda(k)(n) will be called primitive, if there is no l x l submatrix of A that belongs to the set Lambda(k)(l), k <= l < n .The article describes a polynomial algorithm, which works in time O(n(2)) for verifying whether a Lambda(k)(n)-matrix is primitive. The work applies this algorithm for finding all primitive Lambda(k)(n)-matrices which rows and columns are in lexicographically nondecreasing order (semi-canonicalbinary matrices) for some integers n and k.
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