Formalisation of Selected Results from Group Theory

This thesis deals with the formalisation of some group-theoretic results in Isabelle/HOL –
an interactive theorem prover that machine-checks every proof step.
The results include the long-known and well understood fundamental theorem of finitely
generated abelian groups characterising the structure of finitely generated abelian groups as
a uniquely determined product of cyclic groups. Both the invariant factor decomposition
and the primary decomposition are covered. Additionally, some results from the field of
character groups are included, as well as work on formalising the direct product, the internal
direct product and more group-theoretic lemmas – on both the newly introduced definitions
and on already existing definitions from HOL-Algebra – the canonical Isabelle/HOL library
on abstract algebra.