Mathematician · Graph Theory & Combinatorics · Prague, Czech Republic

Sachal Abdullah

An early-career mathematician working on Sheehan's Conjecture and the structure of uniquely Hamiltonian graphs — currently preparing this research for publication.

\[ \text{Sheehan's Conjecture:}\quad \nexists\ G \text{ uniquely Hamiltonian, } G \text{ } k\text{-regular}, \ k \ge 3 \]
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01 About

I am an early-career mathematician with original research experience in graph theory and combinatorics, and I have taught mathematics across secondary and university levels. I am currently continuing research on open problems in uniquely Hamiltonian graphs with the goal of publication, and I am seeking a PhD candidacy where this work can be developed further — I'm also open to a Mathematics Researcher or Teaching Assistant role.

  • Based inPrague, Czech Republic
  • FieldGraph Theory & Combinatorics
  • SeekingPhD Candidacy
  • CVDownload PDF

02 Research

Uniquely Hamiltonian Graphs

Combinatorial Graph Theory & Discrete Mathematics

I explored Sheehan's Conjecture on the non-existence of uniquely Hamiltonian regular graphs. In an attempt to produce an infinite family of uniquely Hamiltonian 4-regular graphs from cubic hypohamiltonian graphs — following a construction due to Fleischner — I showed that in general this construction does not hold for all cubic hypohamiltonian graphs except for the Petersen graph. I demonstrated the limitations of Fleischner's construction by constructing examples via the 1st and 2nd Blanuša snarks. To continue the development of the theory of uniquely Hamiltonian graphs, I formulated a number of open problems which arose from this research. In preparation for a preprint publication.

Supervisor: Dr. Andrew Goodall — Computer Science Institute, Faculty of Mathematics and Physics, Charles University, Prague

Graph Theory Literature & Problems

Combinatorial Graph Theory & Discrete Geometry

Conducted foundational literature reviews and exploratory investigations on uniquely Hamiltonian graphs and the Hadwiger–Debrunner \((p,q)\)-problem. Surveyed the probabilistic method and analysed the Hamiltonian cycle property for bipartite and regular graphs — establishing the theoretical groundwork for subsequent research on Sheehan's Conjecture.

Supervisor: Dr. Mudassir Shabbir — Information Technology University, Lahore

Traffic Regulation Using Game Theory

Algorithmic Modeling, Computer Vision & Reinforcement Learning

Undergraduate thesis: developed an automated, dynamic traffic-signal control system to mitigate urban congestion using computer vision, game theory, and reinforcement learning. The system uses background subtraction with Gaussian distributions to extract real-time vehicle density and velocity from video feeds, then models intersecting roads as competing players within a Markov framework — applying Nash Equilibrium and minimax strategies to optimize green-light durations under live traffic conditions.

Supervisor: Dr. Nazim Ashraf — Department of Computer Science, Forman Christian College, Lahore

03 Publications & Talks

In preparation
Uniquely Hamiltonian graphs from cubic hypohamiltonian graphs — limitations of Fleischner's construction
Working paper, in prep for preprint submission. Supervised by Dr. Andrew Goodall, Charles University, Prague.
2021 · Conference
EuroComb 2021
Participant, International Conference on Graph Theory and Combinatorics — Barcelona
2024 · Talk
Introduction to Graph Theory & Mathematical Problem-Solving
Guest lecture, Czech MENSA Summer Camp — delivered to ~40 gifted students aged 6–18

04 Education

  1. 2022 – 2024

    B.Sc. in Computer Science — Faculty of Mathematics and Physics, Charles University

    Prague, Czechia. Research area: Graph Theory and Combinatorics. Primary thesis research on Sheehan's Conjecture and uniquely Hamiltonian graphs, ongoing in collaboration with supervisor toward publication.

  2. 2013 – 2018

    B.Sc. (Honors) in Computer Science — Forman Christian College

    Lahore, Pakistan. Research area: Game Theory and Artificial Intelligence.

05 Experience

  1. 2025

    Substitute Teacher — International School of Prague

    Served as mathematics and science substitute teacher for middle-school students, covering full lessons independently; occasionally responsible for theatre classes.

  2. 2024

    Guest Lecturer — Czech MENSA Summer Camp, Czechia

    Designed and delivered lectures introducing graph theory and mathematical problem-solving to approximately 40 gifted students aged 6–18.

  3. 2018 – present

    Private Tutor — Mathematics

    Over 6 years of continuous private tutoring in mathematics, working with 10+ students primarily at secondary school and undergraduate computer science level.

  4. 2018 – 2019

    Teaching Assistant — FAST-NUCES, Lahore

    Supported approximately 30 students per semester in an undergraduate Artificial Intelligence course; held office hours, graded assignments, and delivered the mathematical components of lectures.

  5. 2018 – 2019

    Research Assistant — ITU, Lahore

    Surveyed research literature on uniquely Hamiltonian graphs and the Hadwiger–Debrunner \((p,q)\)-problem in preparation for original research.

  6. 2017 – 2019

    Volunteer Teacher — MAKEISTAN (ITU), Lahore

    Delivered mathematics and STEM presentations and assisted with organising educational activities for community outreach programmes.

06 Skills & Activities

Mathematics

Graph Theory, Combinatorics, Analysis, Probability

Teaching

Secondary & Undergraduate Mathematics

Programming

Python, LaTeX, Java

Languages

English (fluent), Urdu (native)

Also: EuroComb 2021 conference participant · volunteer STEM teaching, 2017–2019 · creative writing — poetry, fiction, and non-fiction critique groups.

07 Contact

Reach out about research, collaboration, PhD supervision, or a proof that refuses to close.