Thomas is a software verification expert working at CSE.

Thomas has worked in the field of software verification since 2006, and has contributed to major verification projects, include the seL4 verified microkernel and the CakeML verified compiler. These were significant milestone projects in the field, and remain to this day some of the most substantial pieces of software to have been proven correct.

Thomas worked for the UNSW lab of the NICTA research organisation from 2006-2012, working mostly on seL4. He completed his PhD at UNSW from 2013 - 2017, working on the binary analysis of seL4. He was a postdoc at Chalmers University in Sweden 2018-2020, working on dynamic evaluation in the CakeML environment. Thomas then moved to Cambridge University in the UK and worked on CPU security proofs and proof systems for the C language in 2020-2024.

Thomas returned to UNSW in 2024, and rejoined the Trustworthy Systems group where he is working on the Pancake language (part of the CakeML family) and proofs about systems running on seL4.

Thomas is an expert user of the Isabelle/HOL theorem prover, and also the HOL4 system and SMT-based approaches. At UNSW he teaches on topics such as theorem proving and programming language semantics.