@article{oai:niigata-u.repo.nii.ac.jp:00001929,
 author = {Mikami, Kiyoshi and Tamura, Hiroshi and Sengoku, Masakazu and Yamaguchi, Yoshio},
 issue = {10},
 journal = {IEICE transactions on fundamentals of electronics, communications and computer sciences, IEICE transactions on fundamentals of electronics, communications and computer sciences},
 month = {Oct},
 note = {The synchronic distance is a fundamental concept in a Petri net. Marked graphs form a subclass of Petri nets. Given a matrix D, we are interested in the problem of finding a marked graph whose synchronic distance matrix is D. It is wellknown that the synchronic disrance matrix of a marked graph is a distance matrix. In this letter, we give a matrix D such that D is a distance matrix and there does not exist a marked graph whose synchronic distance matrix is D.},
 pages = {1607--1609},
 title = {On a Sufficient Condition for a Matrix to be the Synchronic Distance Matrix of a Marked Graph},
 volume = {E76-A},
 year = {1993}
}