January 16, 2018, Bob Rosebrugh (Mount Allison), Symmetric lenses and cospans
Abstract: A symmetric lens is state synchronization data and synchronization restoration operations between model domains. An asymmetric lens has only one-way data and operations. Some time ago we showed that spans of asymmetric lenses represent symmetric lenses. In the special case that we named (asymmetric) c-lenses the restoration operation satisfies a universal property. We have recently considered cospans of asymmetric lenses. They also generate symmetric lenses and we can now characterize the special case of symmetric lenses which so arise. When the cospan consists of c-lenses then the symmetric lens has a universal property.
(Joint work with Michael Johnson)