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Necessary and sufficient conditions for excitability and transparency are formulated in terms of the parameterization of the dynamics and control matrices, and equivalently, in terms of strict positivity of a matrix of an associate system obtained from the influence graph of the original system. Such conditions are testable through simple algebraic tests involving moderate computational effort.<\/jats:p><\/jats:sec><jats:sec><jats:title content-type=\"abstract-heading\">Practical implications<\/jats:title><jats:p>The practical implications mainly rely on some biological and medical problems where delays are present by nature, excitability means the activation of all the state components under positive controls after a short time in the sense that it cannot remain identically zero. In the same way, it relays on the activation of all the output components under zero controls and non\u2010negative initial conditions.<\/jats:p><\/jats:sec><jats:sec><jats:title content-type=\"abstract-heading\">Originality\/value<\/jats:title><jats:p>The paper extends the concepts of excitability and transparency to dynamic systems with point time\u2010lags which are very common in nature and some practical problems.<\/jats:p><\/jats:sec>","DOI":"10.1108\/03684920910991559","type":"journal-article","created":{"date-parts":[[2009,10,17]],"date-time":"2009-10-17T07:04:13Z","timestamp":1255763053000},"page":"1576-1598","source":"Crossref","is-referenced-by-count":0,"title":["On excitable dynamic systems with delays"],"prefix":"10.1108","volume":"38","author":[{"given":"Manuel","family":"De la Sen","sequence":"first","affiliation":[]}],"member":"140","reference":[{"key":"key2022020620590550200_b1","doi-asserted-by":"crossref","unstructured":"Batkai, A. and Piazzera, S. 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