nLab
restriction

Contents

Definiion

The restriction of a function f:XYf: X \to Y to a subset UU of XX is simply the composite of ff and the inclusion function of UU:

Ui UXfY. U \stackrel{i_U}\to X \stackrel{f}\to Y .

It is often written as f |U:UYf_{|U}: U \to Y, or a variation on that theme.

Revised on November 14, 2017 06:49:31 by Urs Schreiber (46.183.103.17)