A homotopy between continuous functions between topological spaces is called delayed if it starts out being constant near one boundary of the interval.
(If it is constant near both boundaries we say it has sitting instants).
For the unit interval and and any topological spaces, a continuous map is a delayed homotopy (between and if there exist such that for all .
Delayed homotopies appear in an alternative characterization of Dold fibrations. See there for details.
Smoothing of delayed homotopies
If a continuous homotopy between two smooth functions is delayed at both ends of the inerval it may be approximated by a smooth homotopy . See Steenrod-Wockel approximation theorem.
Revised on October 25, 2010 17:16:55
by Urs Schreiber