English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

G noncyclic. If R does not involve all the generators, then G is a nontrivial free product of a free group and a group with one defining relator, and therefore G has no nontrivial abelian normal subgroup. Hence we may assume that G is finitely generated and that R(a, b, c, • ■ ■ ) is cyclically reduced and involves all the generators. We may also assume that R(a, b, c, • • • ) has zero exponent sum on some generator, say a (denoted <ra(R) —0). As is well known (see Magnus [4] or pp. 254-257 in [5]), a presentation of the normal subgroup H of G generated by b, c, • • • is given as follows: Its generators are

On groups with one defining relation having an abelian normal subgroup.