**homotopy theory, (∞,1)-category theory, homotopy type theory**

flavors: stable, equivariant, rational, p-adic, proper, geometric, cohesive, directed…

models: topological, simplicial, localic, …

see also **algebraic topology**

**Introductions**

**Definitions**

**Paths and cylinders**

**Homotopy groups**

**Basic facts**

**Theorems**

In the context of square matrices an *upper triangular matrix* is one all whose entries below the diagonal vanish. Analogously for a *lower triangular matrix*.

- The table of marks of a finite group is a lower triangular matrix over the integers (this Prop.).

See also

- Wikipedia,
*Triangular matrix*

Last revised on January 27, 2019 at 19:48:50. See the history of this page for a list of all contributions to it.