Homotopy Type Theory set > history (Rev #5)

Contents

Definition

A set consists of

  • A type AA
  • A 0-truncator
    τ 0: (a:A) (b:A) (c:a=b) (d:a=b) (x:c=d) (y:c=d)x=y\tau_0: \prod_{(a:A)} \prod_{(b:A)} \prod_{(c:a=b)} \prod_{(d:a=b)} \sum_{(x:c=d)} \prod_{(y:c=d)} x=y

As univalent setoids

A set is a setoid TT where the canonical functions

a:T,b:Tidtoiso(a,b):(a= Tb)(ab)a:T, b:T \vdash idtoiso(a,b):(a =_T b) \to (a \equiv b)

are equivalences

p: a:A b:A(a= Tb)(ab)p: \prod_{a:A} \prod_{b:A} (a =_T b) \cong (a \equiv b)

Examples

See also

References

Revision on April 27, 2022 at 14:47:45 by Anonymous?. See the history of this page for a list of all contributions to it.