Page "Word problem for groups" Paragraph 2

Throughout the history of the subject, computations in groups have been carried out using various normal forms.

These usually implicitly solve the word problem for the groups in question.

In 1911 Max Dehn proposed that the word problem was an important area of study in its own right,, together with the conjugacy problem and the group isomorphism problem.

In 1912 he gave an algorithm that solves both the word and conjugacy problem for the fundamental groups of closed orientable two-dimensional manifolds of genus greater than or equal to 2,.

Subsequent authors have greatly extended Dehn's algorithm and applied it to a wide range of group theoretic decision problems.