Please go back and reformat your question. Use the button that looks like this:
{} Code
on the code you pasted in the window.
Now, this is not an ARRAYFUN error but an ISEQUAL error. ISEQUAL takes two arguments.
isequal(9,8)
isequal(pi,pi)
What are you trying to compare? Do you mean this:
d= arrayfun(@(x) eq(x.x0,t1.x0),g1,'Un',0)