TeXipedia

projlim

Denotes a projective limit in category theory and advanced algebra, representing the limit of an inverse system.

Overview

Essential in advanced mathematics for describing complex algebraic and topological structures through inverse systems of simpler objects.

  • Commonly used in homological algebra and category theory
  • Appears frequently in the study of pro-finite groups and completion theory
  • Important for constructing universal objects and analyzing infinite dimensional structures
  • Often paired with inverse sequences and filtering systems in advanced mathematical proofs

Examples

Defining an inverse limit of a projective system of groups.

proj limnNGn\projlim_{n \in \mathbb{N}} G_n
\projlim_{n \in \mathbb{N}} G_n

Expressing the p-adic completion of a ring R.

Rp=proj limnR/pnRR_p = \projlim_{n} R/p^nR
R_p = \projlim_{n} R/p^nR

Describing the inverse limit of a sequence of topological spaces.

X=proj limiIXiX = \projlim_{i \in I} X_i
X = \projlim_{i \in I} X_i