CV Juan Rada

June, 2024

Personal

• Name: Juan Pablo Rada Rincón

• Office address: Instituto de Matemáticas, Universidad de Antioquia. Medellín, Colombia.

• e-mail: pablo.rada@udea.edu.co

Degrees

• PhD in Mathematics (Universidad de Murcia, Spain, 1996)

• Master’s in Mathematics (Universidad de Los Andes, Venezuela, 1989)

• Bachelor in Mathematics (Universidad de Los Andes, Venezuela, 1983)

Experience

• Professor at the Universidad de Antioquia (UdeA), Medellín-Colombia, since 2012

• Professor at the Universidad Simón Bolívar (USB), Caracas-Venezuela, 2008-2012

• Professor at the Universidad de Los Andes (ULA), Mérida-Venezuela, 1983-2008

• Visiting Professor at the University of Kentucky (UK), Lexington-USA, 2001

Research interest

• Spectral Graph Theory

• Linear Algebra

• Chemical Graph Theory

• Algebra

M.S. / PhD / Postdoc supervised

Supervisor of postdoctorals:

1. Study of graphs via matrix norms, Juan Daniel Monsalve, Universidad de Antioquia, financed by COLCIENCIAS), 2019-2020.

PhD:

1. Spectral norm and energy with respect to a VDB topological index in digraphs, Carlos Espinal, Universidad de Antioquia, in progress.

2. Domination in catacondensed hexagonal systems, Robinson Higuita, Universidad de Antioquia, completed in 2022.

3. Extremal values of energy and trace norm of digraphs, Juan Daniel Monsalve, Universidad de Antioquia, Colombia, completed in 2017.

4. Bounds for the trace norm of (0,1)-matrices and digraphs, Natalia Agudelo, Universidad de Antioquia, Colombia, completed in 2017.

5. Pre-envelopes of commutative rings, Rafael Parra, Universidad de Los Andes, Venezuela, completed in 2011.

6. Cotorsion pairs and adjoint functors, Diego Bravo, Universidad de Los Andes, Venezuela, completed in 2010.

Master:

1. Minimal value of the exponential of the generalized Randic index over trees, Marisol Londoño, Universidad de Antioquia, completed in 2022.

2. Lower bounds for the spectral norm of digraphs, Jazmín García, Universidad de Antioquia, completed in 2022.

3. Energy of matrices, Florencia Cubría, Universidad de la República, Uruguay, completed in 2018.

4. Extremal values of VDB topological indices over graphs, Tatiana Pérez, Universidad de Antioquia, Colombia, completed in 2014.

5. Topological indices over starlike trees, Clara Betancur, Universidad de Antioquia, Colombia, completed in 2014.

6. Vertex-degree-based topological indices over hexagonal systems with fixed number of vertices, Lilia Berrocal, Universidad Simón Bolívar, Venezuela, completed in 2014.

7. Cotorsion pairs and the finitistic dimension conjecture, Marco Pérez, Universidad Simón Bolívar, Venezuela, completed in 2009.

8. Quasi-preenvelopes of rings, Carlos Parra, Universidad de Los Andes, Venezuela, completed in 2009.

9. Upper bounds for the energy of digraphs, Elías Gudiño, Universidad Simón Bolívar, Venezuela, completed in 2009.

10. Projective envelopes of finitely generated modules, Rafael Parra, Universidad de Los Andes, Venezuela, completed in 2008.

11. Nonderogatory digraphs, Diego Bravo, Universidad de Los Andes, Venezuela, completed in 2006.

12. Starlike trees, Franklin Camacho, Universidad de Oriente, Venezuela, completed in 2006.

13. Construction of equienergetic digraphs, Williams López, Universidad de Los Andes, Venezuela, completed in 2006.

14. Energy of digraphs, Ismael Peña, Universidad de Los Andes, Venezuela, completed in 2006.

15. Graphs with maximum energy, Derwis Rivas, Universidad de Los Andes, Venezuela, completed in 2006.

Research papers published:

1.  C. Espinal, I. Gutman, J. Rada, Elliptic Sombor index of chemical graphs, Commun. Comb. Optim. (2024) in press.

2. S. Bermudo, R. Cruz, J. Rada, Vertex-degree function index on tournaments, Commun. Comb. Optim. (2024) in press.

3. R. Cruz, C. Espinal, J. Rada, A matrix approach to vertex-degree-based topological indices, Mathematics 12 (2024) 2043.

4. C. Espinal, J. Monsalve, J. Rada, Spectral norm and energy of a digraph with respect to a VDB topological index, Heliyon 10 (2024) e32016.

5. J. Rada, J.M. Rodríguez, J.M. Sigarreta,  Sombor index and elliptic Sombor index of benzenoid systems, Appl. Math. Comput. 475 (2024) 128756.

6. C. Espinal, J. Rada, Graph energy change due to vertex deletion, MATCH Commun. Math. Comput. Chem. 92 (2024) 89–103.

7. J. Rada, J.M. Rodríguez, J.M. Sigarreta, Optimization problems for variable Randic type lodeg index and other indices, MATCH  Commun. Math. Comput. Chem. 91 (2024) 741–767.

8. J. Rada, J.M. Rodríguez, J.M. Sigarreta, On integral Sombor indices, Appl. Math. Comput. 452 (2023) 128036.

9. R. Farooq, M. Malik, J. Rada, Extremal graphs with respect to the total-eccentricity index, Asian-Eur. J. Math Vol. 16, No. 8 (2023) 2350138.

10. F. Li, Q. Ye, J. Rada, Extremal values of VDB topological indices over F-benzenoids with equal number of edges, Math. Biosci. Eng. 20 (3) (2023) 5169-5193.

11. R. Cruz, J. Monsalve, J. Rada, Randic energy of digraphs, Heliyon 8 (2022) e11874.

12. S. Bermudo, R. Cruz, J. Rada, Vertex-degree-based topological indices of oriented trees, Appl. Math. Comput. 433 (2022) 127395.

13. J. Monsalve, J. Rada, Energy of a digraph with respect to a VDB topological index, Spec. Matrices 10 (2022) 417-426.

14. M. S. Oz, R. Cruz, J. Rada, Computation method of the Hosoya index of primitive coronoid systems, Math. Biosci. Eng. 19 (10) (2022) 9842-9852.

15. J. Rada, Vertex-degree based topological indices of graphene, Polycycl. Aromat. Compd. 42 (4) (2022) 1524-1532.

16. S. Bermudo, R. Higuita, J. Rada, k-domination and total k-domination numbers in catacondensed hexagonal systems, Math. Biosci. Eng. 19 (7) (2022) 7138-7155.

17. R. Cruz, I. Gutman, J. Rada, Hosoya index of VDB-weighted graphs, Discrete Appl. Math. 317 (2022) 18-25.

18. R. Cruz, J. Rada, W. Sánchez, Extremal unicyclic graphs with respect to vertexdegree-based topological indices, MATCH Commun. Math. Comput. Chem. 88 (3) (2022) 481-503.

19. R. Cruz, J. Monsalve, J. Rada, Sombor index of directed graphs, Heliyon 8 (2022) e09035.

20. 13. R. Farooq, S. Akhter, J. Rada, Total eccentricity index of trees with fixed pendent vertices and trees with fixed diameter, Japan J. Indust. Appl. Math. 39 (2022) 443–465.

21. I. Gutman, J. Monsalve, J. Rada, A relation between a vertex-degree-based topological index and its energy, Linear Algebra Appl. 636 (2022) 134-142.

22. R. Cruz, F. Duque, J. Rada, Anacondensed hexagonal systems, Appl. Math. Comput. 418 (2022) 126798.

23. J. Rada, J.M. Rodríguez, J.M. Sigarreta, Weakly discriminating vertex-degree-based topological indices, MATCH Commun. Math. Comput. Chem. 87 (1) (2022) 97-108.

24. R. Cruz, J. Rada, Extremal values of exponential vertex-degree-based topological indices over graphs, Kragujevac J. Math. 46 (1) (2022) 105-113.

25. I. Gutman, I. Redzepovic, J. Rada, Relating energy and Sombor energy, Contrib. Math. 4 (2021) 41–44.

26. J. Rada, J.M. Rodríguez, J.M. Sigarreta, Geometrical properties of chemical graphs, Int. J. Quantum Chem. 121 (23) (2021) e26798.

27. J. Monsalve, J. Rada, Sharp upper and lower bounds of VDB topological indices of digraphs, Symmetry 13 (10) (2021) 1903.

28. S.M. Sheikholeslami, J. Rada, A. Jahanbani, R. Khoeilar, L. Shahbazi, Sharp upper bounds of the F-index of unicyclic graphs, Asian-Eur. J. Math. 14 (9) (2021) 2150166.

29. 22. S. Bermudo, J. Monsalve, J. Rada, Orientations of hexagonal chains with extremal values of the Randic index, Int. J. Quantum Chem. 121 (18) (2021) e26744.

30. R. Cruz, J. Rada, J.M. Sigarreta, Sombor index of trees with at most three branch vertices, Appl. Math. Comput. 409 (2021) 126414.

31. J. Rada, J.M. Rodríguez, J.M. Sigarreta, General properties on Sombor indices, Discrete Appl. Math. 299 (2021) 87-97.

32. S. Bermudo, R. Higuita, J. Rada, Domination in catacondensed hexagonal systems, J. Math. Chem. 59 (2021) 1348-1367.

33. R. Cruz, J. Rada, Extremal values of the Sombor index in unicyclic and bicyclic graphs, J. Math. Chem. 59 (2021) 1098-1116.

34. J. Monsalve, J. Rada, Vertex-degree based topological indices of digraphs, Discrete Appl. Math. 295 (2021) 13-24.

35. 28. R. Cruz, J. Rada, A. Santamaría-Galvis, Extremal values of vertex-degree-based topological indices of coronoid systems, Int. J. Quantum Chem. 121 (6) (2021) e26536.

36. R. Cruz, J. Monsalve, J. Rada, The balanced double star has maximum exponential Second Zagreb Index, J. Comb. Optim. 41 (2021) 544-552.

37. J. García, J. Monsalve, J. Rada, Lower bounds for the spectral norm of digraphs, Linear Algebra Appl. 617 (2021) 151-167.

38. R. Cruz, I. Gutman, J. Rada, Sombor index of chemical graphs, Appl. Math. Comput. 399 (2021) 126018.

39. R. Cruz, M. Londono, J. Rada, Minimal value of the exponential of the generalized Randic index over trees, MATCH Commun. Math. Comput. Chem. 85 (2) (2021) 427-440.

40. J. Monsalve, J. Rada, Extremal spectral radius of graphs of rank 4, Linear Algebra Appl. 609 (2021) 1-11.

41. R. Cruz, F. Duque, J. Rada, Lower bounds for the number of inlets of hexagonal systems, Int. J. Quantum Chem. 120 (19) (2020) e26358.

42. M. Bhat, S. Pirzada, J. Rada, On spectra and real energy of complex weighted digraphs, Linear Multilinear Algebra 68 (5) (2020) 1064-1076.

43. J. Monsalve, J. Rada, On the maximal energy among orientations of a tree, Kuwait J. Sci. 47 (3) (2020) 2-13.

44. R. Cruz, J. Monsalve, J. Rada, On chemical trees that maximize atom-bond connectivity index, its exponential version, and minimize exponential geometric-arithmetic index, MATCH Commun. Math. Comput. Chem. 84 (3) (2020) 691-718.

45. R. Cruz, J. Monsalve, J. Rada, Trees with maximum exponential Randic index, Discrete Appl. Math. 283 (2020) 634-643.

46. R. Cruz, J. Monsalve, J. Rada, Extremal values of vertex-degree-based topological indices of chemical trees, Appl. Math. Comput. 380 (2020) 125281.

47. S. Bermudo, J. Nápoles, J. Rada, Extremal trees for the Randic index with given domination number, Appl. Math. Comput. 375 (2020) 125122.

48. M. Khan, R. Farooq, J. Rada, Corrigendum to Complex adjacency matrix and energy of digraphs, Linear Multilinear Algebra 68 (1) (2020) 220-222.

49. N. Agudelo, J. Monsalve, J. Rada, On the characterization of digraphs with given rank, Linear Algebra Appl. 587 (2020) 215-227.

50. S. Bermudo, R. Higuita, J. Rada, Domination in hexagonal chains, Appl. Math. Comput. 369 (2020) 124817.

51. R. Cruz, J. Monsalve, J. Rada, Maximal Augmented Zagreb index of trees with at most three branching vertices, IEEE Access, 7 (2019) 146652-146661.

52. R. Cruz, J. Rada, The path and the star as extremal values of vertex-degree-based topological indices among trees, MATCH Commun. Math. Comput. Chem. 82 (3) (2019) 715-732.

53. J. Rada, Exponential vertex-degree-based topological indices and discrimination, MATCH Commun. Math. Comput. Chem. 82 (1) (2019) 29-41.

54. F. Li, Q. Ye, J. Rada, The Augmented Zagreb indices of fluoranthene-type benzenoid systems, Bull. Malays. Math. Sci. Soc. 42 (2019) 1119-1141.

55. J. Monsalve, J. Rada, Oriented bipartite graphs with minimal trace norm, Linear Multilinear Algebra 67 (6) (2019) 1121-1131.

56. J. Rada, S. Bermudo, Is every graph the extremal value of a vertex-degree-based topological index?, MATCH Commun. Math. Comput. Chem. 81 (2) (2019) 315-323.

57. M. Bhat, J. Rada, Lower bounds for the energy of weighted digraphs, Linear Multilinear Algebra 67 (4) (2019) 743-755.

58. J. Monsalve, J. Rada, Y. Shi, Extremal values of energy over oriented bicyclic graphs, Appl. Math. Comput. 342 (2019) 26-34.

59. R. Cruz, C. Marín, J. Rada, Vertex-degree-based topological indices over trees with two branching vertices, Kragujevac J. Math. 43 (3) (2019) 399-411.

60. F. Li, H. Broersma, J. Rada, Y. Sun, Extremal benzenoid systems for two modified versions of the Randic index, Appl. Math. Comput. 337 (2018) 14-24.

61. N. Agudelo, J. Rada, M. Rivera, Upper bound for the trace norm of the Laplacian matrix of a digraph and normally regular digraphs, Linear Algebra Appl. 552 (2018) 194-209.

62. R. Cruz, C. Marín, J. Rada, Extremal values of Merrifield-Simmons index for trees with two branching vertices, Kragujevac J. Math. 42 (1) (2018) 97-106.

63. M. Khan, R. Farooq, J. Rada, Complex adjacency matrix and energy of digraphs, Linear Multilinear Algebra 65 (11) (2017) 2170-2186.

64. R. Cruz, F. Duque, J. Rada, Extremal values of the number of inlets and number of bay regions over pericondensed hexagonal systems, MATCH Commun. Math. Comput. Chem. 78 (2) (2017) 469-486.

65. J. Rada, Extremal properties of hexagonal systems, MATCH Commun. Math. Comput. Chem. MCM 20. Bounds in chemical graph theory-Mainstreams, Univ. Kragujevac, Kragujevac (2017) 239-286.

66. D. Bravo, F. Cubría, J. Rada, Energy of matrices, Appl. Math. Comput. 312 (2017) 149-157.

67. R. Cruz, C. Marín, J. Rada, Computing the Hosoya index of catacondensed hexagonal systems, MATCH Commun. Math. Comput. Chem. 77 (3) (2017) 749-764.

68. J. Rada, Vertex-degree-based topological indices of hexagonal systems with equal number of edges, Appl. Math. Comput. 296 (2017) 270-276.

69. J. Rada. Energy of digraphs, MATCH Commun. Math. Comput. Chem. MCM 17. Energy of Graphs-Theory and Applications. Univ. Kragujevac, Kragujevac (2016). 237-276.

70. J.A. de la Peña, J. Rada, On the energy of symmetric matrices and Coulson's integral formula, Rev. Colombiana Mat. 50 (2) (2016) 173-186.

71. J. Monsalve, J. Rada, Energy of strongly connected digraphs whose underlying graph is a cycle. Proyecciones 35 (4) (2016) 395-404.

72. R. Cruz, F. Duque, J. Rada, Hexagonal systems with minimal number of inlets. MATCH Commun. Math. Comput. Chem. 76 (3) (2016) 707-722.

73. N. Agudelo, J.A. de la Peña, J. Rada, Extremal values of the trace norm over oriented trees. Linear Algebra Appl. 505 (2016) 261-268.

74. J. Rada, The zig-zag chain as an extremal value of VDB topological indices of polyomino chains. J. Combin. Math. Combin. Comput. 96 (2016) 103-111.

75. R. Cruz, J. Rada, Extremal values of VDB topological indices over catacondensed polyomino systems. Appl. Math. Sci. 10 (10) (2016) 487-501.

76. J. Monsalve, J. Rada, Bicyclic digraphs with maximal energy. Appl. Math. Comput. 280 (2016) 124-131.

77. N. Agudelo, J. Rada, Lower bounds of Nikiforov´s energy over digraphs. Linear Algebra Appl. 496 (2016) 156-164.

78. J. Rada, Ordering catacondensed hexagonal systems with respect to VDB topological indices. Rev. Mat. Teor. Apl. 23 (1) (2016) 277-289.

79. R. Cruz, J. Rada, Extremal polyomino chains of VDB topological indices. Appl. Math. Sci. 9 (108) (2015) 5371-5388.

80. C. Marín, J. Monsalve, J. Rada, Maximum and minimum energy trees with two and three branched vertices. MATCH Commun. Math. Comput. Chem. 74 (2) (2015) 285-306.

81. R. Cruz, T. Pérez, J. Rada, Extremal values of vertex-degree-based topological indices over graphs. J. Appl. Math. Comput. 48 (1-2) (2015) 395-406.

82. A. Olivieri, J. Rada, A.J. Ríos, Digraphs with few eigenvalues. Util. Math. 96 (2015), 89-99.

83. C. Betancur, R. Cruz, J. Rada, Vertex-degree-based topological indices over starlike trees. Discrete Appl. Math. 185 (2015) 18-25.

84. R. Cruz, I. Gutman, J. Rada, Topological indices of Kragujevac trees. Proyecciones 33 (4) (2014) 471-482.

85. J. Rada, R. Cruz, Vertex-degree-based topological indices over graphs. MATCH Commun. Math. Comput. Chem. 72 (3) (2014) 603-616.

86. J. Rada, The linear chain as an extremal value of VDB topological indices of polyomino chains. Appl. Math. Sci. 8 (103) (2014) 5133-5143.

87. L. Berrocal, A. Olivieri, J. Rada, Extremal values of VDB topological indices over hexagonal systems with fixed number of vertices. Appl. Math. Comput. 243 (2014) 176-183.

88. J. Rada, R. Cruz, I. Gutman, Benzenoid systems with extremal vertex-degree-based topological Indices. MATCH Commun. Math. Comput. Chem. 72 (1) (2014) 125-136.

89. R. Cruz, H. Giraldo, J. Rada, An upper bound for the energy of radial digraphs. Linear Algebra Appl. 442 (2014) 75-81.

90. I. Gutman, R. Cruz, J. Rada, The Wiener index of Eulerian graphs. Discrete Appl. Math. 162 (2014) 247-250.

91. R. Cruz, H. Giraldo, J. Rada, Extremal values of vertex-degree topological indices over hexagonal systems. MATCH Commun. Math. Comput. Chem. 70 (2) (2013) 501-512.

92. R. Cruz, I. Gutman, J. Rada, On benzenoid systems with minimal number of inlets. J. Serb. Chem. Soc. 78 (9) (2013) 1351–1357.

93. J. Rada, I. Gutman, R. Cruz, The energy of directed hexagonal systems. Linear Algebra Appl. 439 (7) (2013) 1825-1833.

94. S. Pirzada, M. Bhat, I. Gutman, J. Rada, On the energy of digraphs. Bull. IMVI 3 (1) (2013) 69-76.

95. J. Rada, R. Cruz, I. Gutman, Vertex-degree-based topological indices of catacondensed hexagonal systems. Chem. Phys. Lett. 572 (2013) 154-157.

96. R. Cruz, I. Gutman, J. Rada, Convex Hexagonal Systems and Their Topological Indices, MATCH Commun. Math. Comput. Chem. 68 (1) (2012) 97-108.

97. D. Bravo, E. Enochs, A. Iacob, O. Jenda, J. Rada, Cotorsion pairs in C(RMod), Rocky Mountain J. Math. 42 (6) (2012) 1787-1802.

98. J. Rada, Bounds for the energy of normal digraphs. Linear Multilinear Algebra 60 (3) (2012) 323-332.

99. C. Parra, R. Parra, J. Rada, Almost preenvelopes of commutative rings. Int. J. Algebra 6 (12) (2012) 595-603.

100. R. Parra, J. Rada, Projective envelopes of finitely generated modules. Algebra Colloq. 18 (Spec 1) (2011) 801-806.

101. E. Gudiño, J. Rada, A lower bound for the spectral radius of a digraph. Linear Algebra Appl. 433 (2010) 233-240.

102. J. Rada, Lower bounds for the energy of digraphs. Linear Algebra Appl. 432 (2010) 2174-2180.

103. F. Camacho, J. Rada, On the characteristic polynomial of starlike trees. Util. Math. 80 (2009) 245-261.

104. J. Rada, The McClelland inequality for the energy of digraphs. Linear Algebra Appl. 430 (2009) 800-804.

105. J. Rada, Nonderogatory directed windmills. Rev. Colombiana Mat. 42 (1) (2008) 61-66.

106. I. Peña, J. Rada, Energy of digraphs, Linear Multilinear Algebra 56 (5) (2008) 565-579.

107. J.A. de la Peña, I. Gutman, J. Rada, Retarded regular graphs are regular or semiregular. Linear Multilinear Algebra 56 (5) (2008) 507-509.

108. J.A. de la Peña, I. Gutman, J. Rada, Estimating the Estrada Index. Linear Algebra Appl. 427 (1) (2007) 70-76.

109. D. Bravo, J. Rada, Non-derogatory unicyclic digraphs. Int. J. Math. Math. Sci. Volume 2007 (2007), Article ID 46851, 8 pp.

110. W. López, J. Rada, Equienergetic digraphs. Int. J. Pure Appl. Math. 36 (3) (2007) 361-372.

111. D. Bravo, J. Rada, Coalescence of difans and diwheels. Bull. Malays. Math. Sci. Soc. 30 (1) (2007) 49-56.

112. I. Gutman, S. Firoozabadi, J.A. de la Peña, J. Rada, On the energy of regular graphs. MATCH Commun. Math. Comput. Chem. 57 (2) (2007) 435-442.

113. J.A. de la Peña, J. Rada, On the multiplicities of eigenvalues of a graph. Acta Math. Hungar. 114 (1-2) (2007) 91-101.

114. B. Zhou, I. Gutman, J.A. de la Peña, J. Rada, L. Mendoza, On spectral moments and energy of graphs. MATCH Commun. Math. Comput. Chem. 57 (1) (2007) 183-191.

115. J. Rada, Randic decomposition of catacondensed systems. Util. Math. 68 (2005) 155-164.

116. J. Rada, C. Uzcátegui, Randic ordering of chemical trees. Discrete Appl. Math. 150 (1-3) (2005) 232-250.

117. J. A. de la Peña, L. Mendoza, J. Rada, Comparing momenta and pi-electron energy of benzenoid molecules. Discrete Math. 302 (1-3) (2005) 77-84.

118. O. Araujo, M. Estrada, D. Morales, J. Rada, Higher order matching polynomial of a graph. Int. J. Math. Math. Sci. 2005:10 (2005) 1565-1576.

119. E. Enochs, J. Rada, Abelian groups which have trivial absolute coGalois group. Czechoslovak Math. J. 55 (2) (2005) 433-437.

120. J. Rada, Variation of the Wiener index under tree transformations. Discrete Appl. Math. 148 (2) (2005) 135-146.

121. J. Rada, Energy ordering of catacondensed hexagonal systems. Discrete Appl. Math. 145 (3) (2005) 437-443.

122. J. Rada, Hexagonal systems with extremal connectivity index. MATCH Commun. Math. Comput. Chem. 52 (2004) 167-182.

123. J. Rada, Second Order Randic Index of Benzenoid Systems. Ars Combin. 72 (2004) 77-88.

124. J. Rada, A. Tineo, Upper and lower bounds for the energy of bipartite graphs. J. Math. Anal. Appl. 289 (2) (2004) 446-455.

125. J. Rada, A. Tineo, Polygonal chains with minimal energy. Linear Algebra Appl. 372 (2003) 333-344.

126. J. Rada, O. Araujo, A recursive formula for the Randic index of a tree, MATCH Commun. Math. Comput. Chem. 49 (2003) 15-21.

127. J. Rada, C. Uzcátegui, Randic Structure of a Graph, Discrete Appl. Math. 128 (2-3) (2003) 447-463.

128. J. Rada, Characteristic polynomial of catacondensed systems, Linear Algebra Appl. 367 (C) (2003) 243-253.

129. J. Rada, Bounds for the Randic Index of Catacondensed Systems, Util. Math. 62 (2002) 155-162.

130. J. Rada, O. Araujo, Higher order connectivity index of starlike trees, Discrete Appl. Math. 119 (3) (2002) 287-295.

131. O. Araujo, J. Rada, Vertex and Edge Type Relations of Randic Index for Chemical Trees, Ars Combin. 62 (2002) 65-78.

132. I. Gutman, O. Araujo, J. Rada, Matchings in Starlike Trees, Appl. Math. Lett. 14 (2001) 843-848.

133. J. Rada, O. Araujo, I. Gutman, Randic index of benzenoid systems and phenylenes, Croat. Chem. Acta 74 (2001) 225-235.

134. I. Gutman, O. Araujo, J. Rada, An identity for Randic's connectivity index and its applications, ACH-Models Chem. 137 (2000) 653-658.

135. O. Araujo, J. Rada, Randic index and lexicographic order, J. Math. Chem. 27 (3) (2000) 201-212.

136. I. Gutman, J. Rada, O. Araujo, The Wiener index of starlike trees and a related partial order, MATCH Commun. Math. Comput. Chem. 42 (2000) 145-154.

137. J. Rada, M. Saorín, A. del Valle, Reflective Subcategories, Glasg. Math. J. 42 (2000) 97-113.

138. J. Rada, M. Saorín, On two open problems about embedding of modules in free modules, Comm. Algebra 27 (1) (1999) 105-118.

139. J. Rada, M. Saorín, Rings characterized by pre-envelopes and pre-covers of modules, Comm. Algebra 26 (3) (1998) 899-912.

140. J. Rada, M. Saorín, On semiregular rings whose finitely generated modules embeds in free modules, Canad. Math. Bull. 40 (2) (1997) 221-230.

Books published:

1. J. Rada, Introducción al álgebra lineal. Consejo de Publicaciones de la Universidad de Los Andes, 2011.

2. J. Rada and A. Ríos, Introducción a la teoría espectral de digrafos. Ediciones IVIC, 2011.

3. J. Rada, Introducción a la energía de grafos, Editorial Universidad de Antioquia, 2022.

Member of the editorial board for:

1. MATCH-Communications in Mathematical and in Computer Chemistry.

2. Kragujevac Journal of Mathematics.

Reviewer for:

1. Mathematical Reviews.

2. zbMATH.

Talks given in conferences and seminars:

1. Graph energy change due to vertex deletion. Tercera Conferencia Colombiana de Matemáticas Industriales MAPI 3, Universidad Industrial de Santander, Bucaramanga, Colombia, 2024.

2. Energy and topological indices of digraphs. XXIII Congreso Colombiano de Matemáticas, Universidad Pedagógica y Tecnológica de Colombia, Tunja, 2023.

3. Energy and topological indices of digraphs. Seminario Institucional, Instituto de Matemáticas, Universidad de Antioquia, Medellín, Colombia, 2022.

4. Energy of graphs. Primer encuentro Sur Occidental de matemática y matemáticas aplicadas. Universidad del Valle, Cali, Colombia, 2019.

5. Oriented bipartite graphs with minimal trace norm. Encuentro de Sociedades Matemáticas de Colombia y México, Universidad del Norte, Barranquilla, Colombia, 2018.

6. Trace norm of directed graphs. Centro de Estudios de Matemáticas, Universidad Industrial de Santander, Bucaramanga, Colombia, 2017.

7. Generalizations of graph energy. Center of Combinatorics Seminar in University of Nankai, Tianjin, China, 2017.

8. Generalizations of graph energy. 1er Workshop en Algebra, Medellín, Colombia, 2017.

9. Introduction to spectral digraph theory. Encuentro Regional de Matemáticas, Medellín, Colombia, 2015.

10. Bounds of Nikiforov's energy for digraphs. Seminario de Álgebra del IMERL, Montevideo, Uruguay, 2015.

11. Bounds of Nikiforov's energy for digraphs. Seminario de Álgebra del CIMAT, Guanajuato, México, 2015.

12. Generalization of the energy of graphs to directed graphs. International Conference in Homological Algebra, Lexington, USA, 2015.

13. Maximum and minimum energy trees with two branched vertices. 2da. Escuela Colombiana de Matemáticas, Medellín, Colombia, 2014.

14. Energy of directed hexagonal systems. ICAMI 2013, San Andrés, Colombia, 2013.

15. Interaction between algebra and graph theory. ASOVAC, Universidad Central de Venezuela, Maracay, 2011.

16. Topological indices over hexagonal systems. Rafa Fest, Bucaramanga, Colombia, 2011.

17. Introduction to the spectral theory of digraphs. EMALCA, Mérida, Venezuela, 2011.

18. Bounds for the low energy of digraphs. Banff International Research Station, Banff, Canada, 2011.

19. Lower bounds of the spectral radius of a digraph. XXIII Jornadas de Matemáticas Venezolanas; Caracas, Venezuela, 2010.

20. Projective envelopes of finitely generated modules. XXII Jornadas de Matemáticas Venezolanas; San Cristóbal, Venezuela, 2009.

21. Envelopes and covers of modules. EMALCA, Mérida, Venezuela, 2008.

22. The McClelland inequality for the energy of digraphs. Workshop on Spectral Graph Theory; Río de Janeiro, Brasil, 2008.

23. Non-derogatory directed windmills. XXI Jornadas de Matemáticas Venezolanas; Barquisimeto, Venezuela, 2008.

24. Retarded regular graphs. XX Jornadas de Matemáticas Venezolanas; Caracas, Venezuela, 2007.

25. A generalization of the energy to digraphs. Third International Conference on Applied Mathematics, Plovdiv, Bulgaria, 2006.

26. Multiplicity of the eigenvalues of a graph. XIX Jornadas de Matemáticas Venezolanas; Cumaná, Venezuela, 2006.

27. Energy of hexagonal systems. Seminario de Representaciones de Álgebras, UNAM, DF, México, 2006.

28. Generalization of the energy to digraphs. Joint Meeting of the Canadian and Mexican Mathematical Societies, Guanajuato, México, 2006.

29. Energy of hexagonal systems. Seminario de Representaciones de Álgebras, UNAM, DF, México, 2005.

30. Extremal values of the energy and the connectivity index over hexagonal systems. Universidad de Antioquia, Medellín, 2004.

31. Randic index of benzenoid systems + Abelian groups which have trivial absolute cogalois group. Seminario de Representaciones de Álgebras, UNAM, DF, México, 2001.

32. Randic index of benzenoid systems and phenylenes. The Harry Wiener International Memorial Conference on the Role of Topology in Chemistry; Athens, USA, 2001.

33. Generalized Randic index sequence. Workshop in Mathematical Chemistry; Duluth, USA, 2000.

34. Reflective subcategories. Some Trends in Algebra; Praga, Czech Republic, 1999.

35. Duplication of the cube. Olimpíadas Matemáticas Venezolanas; San Antonio de los Altos, Venezuela, 1998.

36. Envelopes and covers of modules in arbitrary classes. XI Jornadas de Matemáticas Venezolanas; Cumaná, Venezuela, 1998.

37. Rings characterized by envelopes and covers of their modules. Euroconference in Ring Theory; Murcia, Spain, 1998.

38. Rings characterized by envelopes and covers. Seminario de Álgebra, Bucarest, Rumania, 1998.

39. Open problems on the inmersion of f.g. modules in free modules. X Jornadas de Matemáticas Venezolanas; Caracas, Venezuela, 1997.

40. Inmersion of cyclic and f.g. modules in free modules. Primeras Jornadas Españolas en Teoría de Anillos; Murcia, Spain, 1996.

41. Rings whose modules embed in projectives. Some trends in Algebra; Praga, Czech Republic, 1995.

Invitations:

1. Center of Combinatorics at University of Nankai, Tianjin, China, 2017.

2. Instituto de Matemáticas y Estadística IMERL, Montevideo, Uruguay, 2015.

3. Centro de Investigación en Matemáticas, A.C. (CIMAT), Guanajuato, México, 2015.

4. Fronteras de la Ciencia, ASOVAC , Maracay, Venezuela, 2011.

5. Rafa Fest, Bucaramanga, Colombia, 2011.

6. Latin American and Caribbean School of Mathematics, Merida, Venezuela, 2011.

7. Banff International Research Station, Banff, Canada, 2011.

8. University of Kentucky, USA, 2010.

9. Latin American and Caribbean School of Mathematics, Merida, Venezuela, 2008.

10. Instituto de Matemáticas de la UNAM, México, 2006.

11. Instituto de Matemáticas de la UNAM, México, 2005.

12. Universidad de Antioquia, Medellín, Colombia, 2004.

13. Instituto de Matemáticas de la UNAM, México, 2001.

14. University of Kentucky, USA, 2001.

15. Coordinador de las XV Olimpíada Iberoamericana de Matemáticas (OIM), Caracas, Venezuela, 2000. 

16. Olimpíada Matemática Venezolana, Caracas, 1998.

17. University of Bucharest, Romania, 1998.

18. Universidad de Murcia, Spain, 1998.