On a group-theoretical generalization of the Gauss formula (with G. Fasolă), The days of the "Al. I. Cuza" University of Iaşi, October 2026.

Sequenceable groups (with I.C. Pleşca), The days of the "Al. I. Cuza" University of Iaşi, October 2026.

The Chermak-Delgado lattice of a finite group, Faculty of Mathematics and Informatics, "Transilvania" University of Braşov, July 2026.

Minimal (just) non-sequenceable groups (with I.C. Pleşca), International Conference MACOS 2026, Braşov, June 2026.

Harmonic mean of element orders of a finite group (with I.C. Pleşca), ICAPM 2025, Iaşi, November 2025.

Completely realisable groups - a step in inverse group thepry (with G. Fasolă), ICAPM 2025, Iaşi, November 2025.

Harmonic mean of element orders of a finite group (with I.C. Pleşca), The days of the "Al. I. Cuza" University of Iaşi, October 2025.

From number theory to group theory (with I.C. Pleşca), The days of the "Al. I. Cuza" University of Iaşi, October 2024.

Completely realisable groups (with G. Fasolă), The days of the "Al. I. Cuza" University of Iaşi, October 2024.

From number theory to group theory (with I.C. Pleşca), International Conference MACOS 2024, Braşov, June 2024.

On the harmonic mean of element orders of a finite group (with I.C. Pleşca), The days of the "Al. I. Cuza" University of Iaşi, October 2023.

On the Chermak-Delgado lattice of a finite group (with G. Fasolă), The days of the "Al. I. Cuza" University of Iaşi, October 2023.

On the size of coset unions, The days of the "Al. I. Cuza" University of Iaşi, October 2022.

Finite groups with a certain number of values of the Chermak-Delgado measure, The days of the "Al. I. Cuza" University of Iaşi, October 2021.

On the sum of element orders of a finite group (with M.S. Lazorec), The days of the "Al. I. Cuza" University of Iaşi, October 2020.

A generalization of the Euler's totient function and its applications, The days of the "Al. I. Cuza" University of Iaşi, October 2019.

On the Chermak-Delgado lattice of a finite group, The days of the "Al. I. Cuza" University of Iaşi, October 2018.

The Chermak-Delgado lattice of a finite group, The days of the "Al. I. Cuza" University of Iaşi, October 2017.

Criterii de comutativitate a grupurilor, Mathematics Teaching Seminar, Faculty of Mathematics, "Al. I. Cuza" University of Iaşi, March 2017.

A new poset associated to finite groups, The days of the "Al. I. Cuza" University of Iaşi, October 2016.

Sum-free sets in groups and hypergroups (with I. Tofan), The days of the "Al. I. Cuza" University of Iaşi, October 2015.

Subgroup commutativity degrees of finite groups, The days of the "Al. I. Cuza" University of Iaşi, October 2015.

Gradul de comutativitate al grupurilor finite, National Conference of SSMR, Iaşi, October 2014.

The posets of classes of isomorphic subgroups of finite groups, The days of the "Al. I. Cuza" University of Iaşi, October 2013.

Ireductibilitate în inele de polinoame, The days of the "Al. I. Cuza" University of Iaşi, October 2012.

Solitary quotients of finite groups, The days of the "Al. I. Cuza" University of Iaşi, October 2012.

Pseudocomplementation in (normal) subgroup lattices, The days of the "Al. I. Cuza" University of Iaşi, October 2011.

A probabilistic aspect of finite group theory, The days of the "Al. I. Cuza" University of Iaşi, October 2011.

A note on subgroup coverings of finite groups, The days of the "Al. I. Cuza" University of Iaşi, October 2009.

Finite groups determined by an inequality of the orders of their subgroups, The days of the "Al. I. Cuza" University of Iaşi, October 2009.

On the lattice of fuzzy subgroups of a finite group, The days of the "Al. I. Cuza" University of Iaşi, October 2008.

E-lattices and their applications, The days of the "Al. I. Cuza" University of Iaşi, October 2006.

Complementation in normal subgroup lattices (a survey), The Annual Symposium on Mathematics Applied in Biology & Biophysics, "Ion Ionescu de la Brad" University of Iaşi, June 2006.

Complementation in subgroup lattices (a survey), The Annual Symposium on Mathematics Applied in Biology & Biophysics, "Ion Ionescu de la Brad" University of Iaşi, June 2006.

A generalization of the lattice concept and its applications, The days of the "Al. I. Cuza" University of Iaşi, October 2005.

A note on U-decomposable groups, The Annual Symposium on Mathematics Applied in Biology & Biophysics, "Ion Ionescu de la Brad" University of Iaşi, May 2005.

On the group of autoprojectivities of an abelian p-group, Anniversary Symposion of "Gr. C. Moisil" Seminar, Iaşi, May 2005.

L-isomorphisms of groups, The days of the "Al. I. Cuza" University of Iaşi, October 2004.

On groups whose lattices of subgroups are pseudo-complemented, International Conference ECIT 2004, Iaşi, July 2004.

A special class of groups (U-decomposable groups), The Annual Symposium on Mathematics Applied in Biology & Biophysics, "Ion Ionescu de la Brad" University of Iaşi, May 2004.

Fundamental group lattices and applications, The days of the "Al. I. Cuza" University of Iaşi, October 2003.

An application of the group theory, International Conference SSIA 2003, Iaşi, September 2003.

Actions of finite groups on lattices, National School of Algebra, Eforie Nord, Constanţa, September 2003.

On the groups associated to genetic recombinations, The Annual Symposium on Mathematics Applied in Biology & Biophysics, "Ion Ionescu de la Brad" University of Iaşi, May 2003.

On the subgroup lattice of a semidirect product of finite cyclic groups, The days of the "Al. I. Cuza" University of Iaşi, October 2002.

On the subgroup lattice of an abelian finite group, International Conference ECIT 2002, Iaşi, July 2002.

Communications at Algebra Seminar, Faculty of Mathematics, "Al. I. Cuza" University of Iaşi.