Responsa for Eruvin 123:6
ור"מ סבר זמנין דמקרי ודייר ואמרו רבנן אין עירוב מועיל במקום עכו"ם ואין ביטול רשות מועיל במקום עכו"ם עד שישכיר ועכו"ם לא מוגר
deeds. R'Eliezer B'Jacob holds that, since a heathen is suspected of bloodshed,<span class="x" onmousemove="('comment',' Cf. A.Z. 22a.');"><sup>12</sup></span> a preventive measure has been enacted by the Rabbis in the case of two Israelites, who quite frequently live together with a heathen, but not in that of one Israelite who as a rule does not live together with a heathen,<span class="x" onmousemove="('comment',' Against something unusual no enactment was deemed necessary. Hence R. Eliezer b. Jacob's ruling that the restrictions applied to a courtyard in which no less than two Israelites were the heathen's neighbours.');"><sup>13</sup></span>