Thirteenth Conference "APPLICATION OF MATHEMATICS IN TECHNICAL AND NATURAL SCIENCES" June 24-29, 2021, Albena, BULGARIA E-mail: conference@eac4amitans.eu Title: Surname: First name: Second name: Institution: Position: Mailing Address: Postal code: City: Country: Phone: Fax: E-mail: Section: (Applied Analysis, Applied Physics, Biomathematics, Continuum Mechanics, Mathematical Physics, Numerical Methods, Scientific Computing, Solitons and Transport Processes, ss "Stochastic and Statistic Modelling", ss "Mikhail Ostrogradsky 220", ss "Geometric Methods in Science and Technics", session on honor of Prof. C.I. Christov (1951-2012) 70th birthday) Contribution title, authors and short abstract within 300 words: Accompanying person(s): Itinerary inside Bulgaria: Arrival: Departure: