errorCount = try_failure(errorCount, "plusEquals... ",
"(C = A - B, but C = C + B != A)");
}
A = R.uminus();
try {
check(A.plus(R), Z);
try_success("uminus... ", "");
} catch (java.lang.RuntimeException e) {
errorCount = try_failure(errorCount, "uminus... ",
"(-A + A != zeros)");
}