Reference for Sanhedrin 9:9
וכי מאחר דלא מהני רבה בר חנה רשותא דנקט למה לי לעיירות העומדים על הגבולין
<i>and a</i> lawgiver … this refers to the descendants of Hillel [in Palestine] who teach the Torah in public. Is, however, a permission given 'there' valid 'here'? Come and hear! Rabbah b. Hana gave an erroneous judgment [in Babylonia]. He then came before R. Hiyya, who said to him: If both parties accepted you as their judge, you are not liable to make restitution; otherwise you must indemnify them. Now — Rabbah b. Hana did hold permission [but from the Palestinian authority]. Hence we infer that the Palestinian authorisation does not hold good for Babylon.<span class="x" onmousemove="('comment',' Otherwise he should not have been liable to indemnification. ');"><sup>6</sup></span>