I am a dreamer. A naïve dreamer. I am a naïve and optimistic dreamer. This combination can be lethal for a man. And still, I navigate through life with these talents.

I send a grateful thought to teacher Neculae Cojocaru and Professor Tiberiu Popoviciu.

Over the years, I’ve been fascinated by various mathematics and computer science problems. I think a considerable part of my activity has been the intertwinement between pure mathematics, applied mathematics and software development. Throughout the years, I have explored these passions in various publications.

Inspired by Professor T. Popoviciu’s suggestion I studied the minimum number of multiplications needed to calculate the value of a fundamental polynomial of the interpolation polynomial of Lagrange[1] and the best bounds for successive permutations[2].

I began my career (under the laws back then) at a territorial calculation center in Cluj-Napoca, Romania and worked on some interesting programs written in assembly language[3]. Around the same time, my interest was sparked by problems relating to burning in an axial-symmetric combustion chamber and Navier-Stokes equations. The programs in question were written in FORTRAN.

My interest towards the Fubini numbers materialized in publications [8], [11] and [18].

For a long period of time I was fascinated by a few qualitative problems regarding differential equations, mostly the 16^{th} problem of D. Hilbert regarding limit cycles. This interest is also reflected in publications [13], [14], [15], [16], [17], [19], [20], [21], [22], [25], [26], [28], [29], [32], [37], [39], [41] and [45]. My best publications on this list are [37], [41] and [45].

For another period of time I investigated different types of numerical integration methods of differential equations (implicit, semi-explicit and reduced number of evaluations at every step). Publications [23], [24] and [27] reflect this interest.

A lot of qualitative aspects of the differential inclusions were studied in publications [30], [31], [33], [34], [35], [36], [38], [40] and [48]. My best publications around this topic are [34], [35] and [40].

My fascination for applications of various economics problems is explored in publications [42], [43], [46], [47], [49] and [50].

The controllability of differential equations and differential inclusions is an important subject relating to optimal control and to the qualitative theory of differential inclusions. See publications [44], [48], [51], [53] about this topic, particularly number [52].

A fascinating topic is the approximation of multifunctions and my interest in this topic is highlighted in publications [54] and [55].

A new method of studying classic and modern problems involves using calculation and graphics software. I’ve opted for the Mathematica® package and using this software I wrote a study about the problem of brachistochrone curves with/without friction and with/without initial velocity as well as the problem of moon landing in certain conditions. Publications [56], [57], [58] and [59] look at this issue in more detail.

Out of all the books I’ve written so far, the one that brought me the most satisfaction was the last one, publication [9] in the List of books. The title of the book contains the word ‘concrete’. Approximately 20 years ago, *Concrete Mathematics* was published, by L. Graham, D. E. Knuth and O. Patashnik, Addison-Wesley, 1994. This book underlines the necessity of a vision regarding concrete aspects of mathematical analysis. The book contains a lot of competition level problems, combinations related to the calculation of pi (the BBP method and others), the W-Z method, algorithm analysis and many others. With my book, I wanted to demonstrate that a first year maths or computer science student can tackle problems that might seem difficult at first sight. Now I am hoping to finish the second edition, which will have many more applications and will rely more on the use of the Mathematica® software.

Because I am a naïve and optimistic dreamer, I hope to make progress in the writing of a book about variation calculus and optimal control. The book will comprise of a few chapters relating to smooth and a few chapters relating to nonsmooth aspects. I am also hoping that many if not all problems will have calculations and figures made with Mathematica®.

[1] A combinatorial problem connected to the Lagrange interpolation polynomial, in T. Popoviciu, Numerical Analysis. Introductory Notions of Approximative Calculus, Editura Academiei RSR, 1975, p. 190, Romanian

[2] Best evaluations to the lower and upper bounds of the number of successive permutations satisfying a minimum condition, in my Master thesis, Cluj, 1975, Romanian

[3] (2, 3, 4 and 7 in the Publications list)