categorical product
积
Meaning in context
Objects P with projections to a specified family such that every matching family of maps from any X arises uniquely from a map X→P.
配有到指定对象族的投影的对象 P,使从任意 X 出发的相应映射族都唯一来自 X→P 的态射。
Example
The product of sets and has two ordered pairs.
Usage and distinctions
The product includes its projections; in a poset it is a greatest lower bound.
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Recommended reading in this subject · Preparation & skip guidance
Definition sources
- Emily Riehl — Category Theory in Context (current second-edition draft)§3.1, Definition 3.1.9 · Checked 2026-10-14
Translation sources
- 李文威 — 代数学方法,第一卷(作者源码)第2章,「极限」,有限极限讨论,积与余积的第一项 · Checked 2026-10-14