Claim: Michael Elmhirst Cates, the 19th Lucasian Professor of Mathematics at the University of Cambridge, proposed that jammed systems differ from ordinary solids in that if the direction of the applied stress changes, the jam will break up; and sometimes, the change of direction required is very small.
Evidence: He is the 19th Lucasian Professor of Mathematics at the University of Cambridge and has held this position since 1 July 2015.