In this Survey of blog and wiki posts on Relation Theory, relations are viewed from the perspective of combinatorics, in other words, as a topic in discrete mathematics, with special attention to finite structures and concrete set-theoretic constructions, many of which arise quite naturally in applications.  This approach to relation theory is distinct from, though closely related to, its study from the perspectives of abstract algebra on the one hand and formal logic on the other.

Elements

• Relation Theory

Relational Concepts

Illustrations

• Six Ways of Looking at a Triadic Relation ⌬ 1

Blog Series

• Relation Theory • (1) • (2) • (3) • (4) • (5) • (6)
• Discussions • (1) • (2) • (3)

• Relations & Their Relatives • (1) • (2) • (3)
• Comments • (1) • (2) • (3)
• Discussions • (1) • (2) • (3) • (4) • (5) • (6) • (7) • (8) • (9) • (10) • (11) • (12) • (13) • (14) • (15) • (16) • (17) • (18) • (19) • (20) • (21) • (22) • (23)
• Reviews • (1)

• Triadic Relations • (1) • (2) • (3)
• Discussions • (1) • (2) • (3)
• Earlier Versions • (1) • (2)

Peirce’s 1880 “Algebra of Logic” Chapter 3

• Preliminaries
• Selections • (1) • (2) • (3) • (4) • (5) • (6) • (7) • (8)
• Comments • (7.1) • (7.2) • (7.3) • (7.4) • (7.5)

Resources

• Peirce’s 1870 Logic Of Relatives