# Stathis Zachos

> mathematician

**Wikidata**: [Q7604112](https://www.wikidata.org/wiki/Q7604112)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Stathis_Zachos)  
**Source**: https://4ort.xyz/entity/stathis-zachos

## Summary

Stathis Zachos is a Greek mathematician and computer scientist known for his foundational work in mathematical logic, computability theory, and algorithmic complexity. Born in Athens in 1947 and educated at ETH Zurich, he has served as a professor at the National Technical University of Athens and maintained academic affiliations with the City University of New York and the University of California, Santa Barbara. With an Erdős number of 2 and over 35 doctoral students spanning decades of academic mentorship, Zachos has significantly influenced the development of theoretical computer science in Greece and internationally.

## Biography

- **Born:** 1947, Athens, Greece
- **Nationality:** Greek
- **Education:** Ph.D. from ETH Zurich (Swiss Federal Institute of Technology Zurich); doctoral advisors included Erwin Engeler and Ernst Specker
- **Known for:** Contributions to mathematical logic, computability theory, and algorithmic complexity; extensive doctoral supervision in theoretical computer science
- **Employer(s):** National Technical University of Athens (Greece), City University of New York (USA), University of California, Santa Barbara (USA)
- **Field(s):** Mathematics, Computer Science, Philosophy, University Teaching

## Contributions

Stathis Zachos has made substantial contributions to theoretical computer science and mathematical logic. His academic lineage through the Mathematics Genealogy Project (ID: 53715) traces to prominent mathematicians, and his Erdős number of 2 connects him directly to Paul Erdős through collaborator connections. He has supervised over 35 doctoral students who have themselves become productive researchers in algorithms, cryptography, computational complexity, and related fields. His publications are indexed in major academic databases including DBLP (author ID: 10/2770), Scopus (author ID: 6603171012), Google Scholar (author ID: efX6PdsAAAAJ), and zbMath (author ID: zachos.stathis-k). His work has contributed to the establishment of Greece as a center for theoretical computer science research in southeastern Europe.

## FAQs

**What is Stathis Zachos's educational background?**
Stathis Zachos earned his Ph.D. from ETH Zurich (Swiss Federal Institute of Technology Zurich), one of Europe's premier technical universities, where he was supervised by Erwin Engeler and Ernst Specker, both prominent figures in mathematical logic and set theory.

**Where has Stathis Zachos worked professionally?**
Zachos has held academic positions at three major institutions: the National Technical University of Athens (Greece), where he has been a long-standing faculty member; the City University of New York in the United States; and the University of California, Santa Barbara.

**How many doctoral students has Stathis Zachos supervised?**
Stathis Zachos has supervised at least 35 doctoral students according to the Mathematics Genealogy Project, including notable researchers such as Aggelos Kiayias (cryptographer), George Kollios, Michael Lampis, and Valia Mitsou, among many others.

**What is Stathis Zachos's Erdős number?**
Stathis Zachos has an Erdős number of 2, indicating that he has co-authored papers with mathematicians who directly co-authored with Paul Erdős, placing him in a close academic network to one of the most prolific mathematicians of the 20th century.

**What are Stathis Zachos's main research areas?**
His primary fields include mathematics, computer science, philosophy, and university teaching, with specific contributions to mathematical logic, computability theory, and algorithmic complexity.

**What is Stathis Zachos's native language?**
His name in native Greek is Στάθης Ζάχος (Stathis Zachos), and he speaks and writes in both English and Modern Greek.

## Why They Matter

Stathis Zachos matters because he has been instrumental in building the theoretical computer science community in Greece. As a professor at the National Technical University of Athens, one of Greece's most prestigious institutions, he has trained generations of researchers who have gone on to populate academic departments and research institutions worldwide. His position as a bridge between European (particularly Swiss) mathematical tradition and American computer science has facilitated intellectual exchange. The sheer volume of his doctoral supervision—over 35 students—represents a remarkable contribution to academic genealogy in his field. His Erdős number of 2 places him among mathematically well-connected scholars, and his indexed publications in multiple major databases demonstrate sustained scholarly output over decades. Without his mentorship and leadership, the landscape of theoretical computer science research in Greece would be significantly diminished.

## Notable For

- **Academic Genealogy:** Erdős number 2, connecting directly to Paul Erdős through collaboration networks
- **Doctoral Supervision:** Over 35 completed Ph.D. students through the Mathematics Genealogy Project
- **International Recognition:** Indexed in DBLP, Scopus, Google Scholar, zbMath, and Mathematics Genealogy Project
- **Institutional Leadership:** Long-standing faculty member at National Technical University of Athens (sitelink count: 27 for the university)
- **Cross-Continental Impact:** Academic affiliations in Greece, USA (City University of New York, UC Santa Barbara), educated in Switzerland
- **Multilingual Scholarship:** Published in both English and Modern Greek

## Body

### Early Life and Education

Stathis Zachos was born in 1947 in Athens, Greece. His academic journey led him to pursue doctoral studies at ETH Zurich (Swiss Federal Institute of Technology Zurich), one of the world's leading technical universities. At ETH Zurich, he was mentored by two distinguished mathematicians: Erwin Engeler (born 1930, Swiss mathematician and computer scientist, professor at ETH Zurich) and Ernst Specker, both of whom were pivotal figures in mathematical logic and set theory. This Swiss education provided Zachos with a rigorous foundation in mathematical reasoning that would underpin his subsequent career in theoretical computer science.

### Academic Career and Institutional Affiliations

Zachos's academic career has spanned multiple prestigious institutions across three countries. His primary affiliation has been with the National Technical University of Athens (NTUA), one of Greece's oldest and most respected universities, founded in 1836. NTUA, headquartered at Heroon Polytechniou 9, Zografou, Athens, with postal code 15780, has been Zachos's main professional base where he has taught and supervised generations of graduate students.

In addition to his position in Greece, Zachos has held academic appointments in the United States. He has been affiliated with the City University of New York (CUNY), a major public university system, and the University of California, Santa Barbara (UCSB), a renowned research institution. These international connections have allowed him to bridge European mathematical traditions with American computer science research cultures.

### Doctoral Supervision and Academic Genealogy

One of Zachos's most significant contributions to academia is his extensive doctoral supervision. He has supervised over 35 Ph.D. students according to the Mathematics Genealogy Project, making him one of the most prolific doctoral advisors in theoretical computer science in Greece. His doctoral students include:

- **George Kollios** (Ph.D., Polytechnic University, 2000) — now a university teacher and computer scientist
- **Aggelos Kiayias** — Greek cryptographer and computer scientist
- **Michael Lampis** (Ph.D., City University of New York, 2011) — computer scientist
- **Valia Mitsou** (Ph.D., City University of New York, 2014) — computer scientist
- **Yu Lin-Kriz**
- **Yannis Maistros**
- **Christos Nomikos**
- **Aris T. Pagourtzis**
- **Kiron Sharma**
- **Costas Koutras**
- **Euripides A. Markou**
- **Katerina Potika**
- **Barry Cohen**
- **Petros Potikas**
- **Panos Hilaris**
- **Kostas Fragos**
- **Christodoulos Fragoudakis**
- **Rave Harpaz**
- **Islam A. T. F. Taj-Eddin**
- **Apostolos Fertis**
- **Evangelos Bampas**
- **Vassilis Zikas**
- **Nikos Leonardos**
- **Panagiotis Cheilaris**
- **Wen-Ju Cheng**
- **Aris Tentes**
- **Thanasis Lianeas**
- **Tayfun Pay**
- **Antonis Achilleos**
- **Stratis Ioannidis**
- **Dimitris Sakavalas**
- **Konstantinos Pouliasis**
- **Konstantinos Nikolopoulos**
- **Timotheos Aslanidis**
- **Eleni Bakali**

This extensive list demonstrates Zachos's profound influence on the development of theoretical computer science researchers, many of whom have themselves become faculty members, researchers, and industry professionals worldwide.

### Research Contributions and Scholarly Output

Stathis Zachos's scholarly work is documented across multiple academic databases, indicating sustained research output over decades. His publications are indexed in:

- **DBLP** (Digital Bibliography & Library Project): author ID 10/2770
- **Scopus**: author ID 6603171012
- **Google Scholar**: author ID efX6PdsAAAAJ
- **zbMath** (Zentralblatt MATH): author ID zachos.stathis-k
- **Mathematics Genealogy Project**: ID 53715
- **MR Author ID**: 186130
- **Freebase ID**: /m/0h1gj64
- **Wikidata**: 

His research falls primarily within the domains of mathematics, computer science, and philosophy, with specific contributions to mathematical logic, computability theory, and algorithmic complexity. While the specific titles of his publications are not enumerated in the source material, his indexing across multiple major academic databases confirms his status as a productive and recognized scholar.

### Professional Recognition and Network Position

Zachos's Erdős number of 2 is particularly noteworthy. This metric, measuring the "collaborative distance" between a mathematician and Paul Erdős, places Zachos in a close academic network to one of the most influential mathematicians of the 20th century. An Erdős number of 2 means that Zachos has co-authored papers with mathematicians who directly co-authored with Erdős, placing him in an elite category of academically well-connected researchers.

His sitelink count of 1 (Wikipedia) and wikidata_description of "mathematician" confirm his presence in major knowledge bases, while his membership in WikiProject Mathematics indicates ongoing engagement with the mathematical community.

### Legacy and Influence

Stathis Zachos's legacy manifests in multiple dimensions. First, his educational mentorship has created a network of over 35 doctoral descendants who carry forward his intellectual traditions. Second, his cross-continental career—spanning Switzerland (education), Greece (primary employment), and the United States (visiting appointments)—has facilitated international exchange of ideas. Third, his position at the National Technical University of Athens has contributed to establishing Greece as a center for theoretical computer science research in southeastern Europe. Fourth, his Erdős number of 2 connects him to a global network of mathematicians and computer scientists. Without his decades of teaching, supervision, and research, the landscape of theoretical computer science in Greece would be significantly different, with fewer trained researchers and less international connectivity.

## References

1. Mathematics Genealogy Project