We discuss possible experimental tests of the recently proposed SO(5) theor
y of antiferromagnetism (A) and d-wave superconductivity (S) in the high T-
c cuprates. In particular we discuss the expected temperature/doping phase
diagram, the posibility of observing antiferromagnetic vortex cores and pro
ximity effects and Josephson coupling in S-A-S heterostructures. (C) 1998 E
lsevier Science Ltd. All rights reserved.