presentation

《Algebra》 · 第 99 页 · Chapter II，Section 8.2「Presentations」

A presentation of a group $G$ is an explicit isomorphism $G\cong F(A)/R$, where $A$ is a set and $R$ is a subgroup of “relations.” In other words, a presentation is an explicit surjection $\rho:F(A)\twoheadrightarrow G$ of which $R$ is the kernel.