... became a centre of very profound intellectual development. The cultural evenings on Fridays included characters such as Juan José Arreola, Nabor Carrillo, etc. Art, science and culture on the lips of their creators, was disseminated among these young people giving them the most current ideas of the time. At this high school, Sylvia had one of her dearest friends, Alejandra Jaidar ...

When she arrived, the first thing she knew was that her future students had just had her predecessor fired by going on strike. And the same afternoon that she talked to the director about teaching a class like that, without further ado, they sent her to give her first lesson. The first thing she received from the students was a complaint for having exchanged, on the way to class, the room on the ground floor they had been assigned for another on the first floor which had belonged to a teacher with walking problems. It must be said that almost all of her students were older than Sylvia. So every afternoon she would put on the most serious outfit she could find and come to teach her class. At her home her family laughed at her 'serious teacher disguise'.

That year, 1958, there were many major strikes in Mexico. In particular, there was a student strike against the rise in the price of transportation. The students from Escuela Nacional Preparatoria 3 organised groups, made propaganda and called for a demonstration in the Zócalo (the main square of Mexico City). Of course, they invited their beloved teacher: "we're going for you and we'll take care of you all the way, teacher."

Nearing the end of the course, the students asked Sylvia to teach them Calculus the following year. But she was about to go to Paris and she couldn't do it. The day of the last examination all the students arrived in suits, very handsome. In the end they told Sylvia that they invited her to have a taquito. They, the most forward, the ones with a reputation for being rude and vandals, had reserved a table for their teacher and had hired a mariachi band to say goodbye to her.

Together they shared adventures of all kinds: fishing, diving, radio amateurs and the most demanding of all adventures, having children.

... she has taught in more than fifty courses at the Faculty, has directed bachelor's and master's theses, has been an examiner (in professional, master's and doctoral examinations), has given lectures at national and international congresses, has participated in commissions of the Department of Mathematics of the Consejo Nacional de Ciencia y Tecnología, has been a member of the Board of Directors of the Mexican Mathematical Society, has taught courses at provincial universities, has published research articles and, recently, has devoted her efforts to writing of a book on group actions that will soon be published by the Mexican Mathematical Society.

Symmetries in topological spaces are an additional structure that enriches their study and allows us to refine the statements made about such spaces. These symmetries are formulated in the language of group actions. In general, groups that act on a topological space are also considered to have a topological structure that transforms them into topological groups. Spaces with symmetries, or topological transformation groups, arise in a natural way in theoretical physics and in many branches of mathematics. This book presents the topology of G-spaces in a systematic and orderly way and is a noteworthy contribution to the bibliography of advanced mathematics in Spanish.

... the good thing is that I got Sylvia de Neymet as a student. Very pretty and a very good student, because the rest were "waiting to get married" girls who were at the university because their mothers sent them and Sylvia was definitely not. She was also a very pleasant person to deal with, she talked a lot with me when I left classes, and her participation in them made clear the depth of her thought, her questions were precise and interesting.

I once travelled with her to Hungary, in 1993, to a congress and as a roommate she was ideal, she was very respectful, very prudent. You felt comfortable with her, she was easy to deal with, very fine and rarely got angry. It was to her great merit that being a woman and being in the mathematical environment that was there in its beginning, to do her doctorate and have an academic career. She is the first doctor in Mathematics and is the first woman to do an academic career in Mathematics, and stay to work at a university, to do research in Mathematics.

We were partners in many congresses, academic commissions and seminars. She was one of the first full-time professors in this Mathematics department. We had a great relationship, because we worked on the same thing and we established a relationship of friendship forever. I never heard any gossip or negative comments about anyone from her, she was a person who was highly esteemed herself and therefore esteemed others as well.

The crucial moment of our friendship was the congress in Guanajuato in 1990. Pilar Martínez, Mariana Saiz and I travelled in Sylvia's car; there any ice was broken and we discovered that behind the serious and formal, Sylvia hid a funny woman, joyful and talkative. Sylvia and I shared a room and whole nights of the most delicious conversation. It was two in the morning and we said to each other 'well, now - tomorrow we will continue talking', we turned off the light, and it was enough for one of us to say 'but ... ' so that the light would come on and the talk would go on hour after hour.

We worked together and it was wonderful to be her friend. We paid her a tribute shortly before she retired and, precisely while she was carrying out the retirement procedures, she passed away.

In one way or another, although Sylvia was not my teacher during my undergraduate degree, she was always present: Sylvia, when she greets you, is not being "kind" in the formal sense of the word: she is greeting you. When she asks you how you are, how things are going, your subjects, how your new assistantship is going, how your pregnancy is going, how your babies are, she is telling you that she shares it, that even though you have never talked to her, she is with you.

It was later, in my master's degree, that we really met and I have enjoyed knowing Sylvia ever since. She is the most enthusiastic and passionate person about geometry, topology, and beautiful examples. The hyperbolic geometry seminar in which we participated excited her enormously. There I discovered another part of her personality; her secret identity: Sylvia is "the fastest chalk in the West" ... no proof stands up to her ... an hour is more than enough to unravel the most terrible secrets of any theorem ... it is very difficult to discern what goes faster: chalk, her words, the ideas or the relentless draft ... it is impressive and exhausting. Leaving the seminar it was only possible to share a peaceful coffee.