Commentary for Bava Metzia 47:11

ת"ש המוצא מעות בבתי כנסיות ובבתי מדרשות ובכל מקום שהרבים מצויין שם הרי אלו שלו מפני שהבעלים מתיאשין מהן מאן שמעת ליה דאזיל בתר רובא ר"ש בן אלעזר שמעת מינה אפילו ברוב ישראל נמי

And if you come to the conclusion that they differ even where the majority are heathens, is the law in accordance with his view or not? And if you come to the conclusion that the law is in accordance with his view, does this apply only to the case where the majority are heathens, or also to the case where the majority are Israelites? — Come and hear: If one finds money in a Synagogue or a house of study, or in any other place where crowds are frequent, it belongs to the finder, because the owner has given it up.<span class="x" onmousemove="('comment',' Cf. supra 21b. ');">¹⁰</span>

Rashi on Bava Metzia