Reference for Eruvin 93:2

ומאי קושיא דילמא הכא נמי היכא דאיתמר איתמר היכא דלא איתמר לא איתמר

R'Judah<span class="x" onmousemove="('comment',' Who was explicitly named.');">⁴</span> of course; but has it not been laid down that 'In a dispute between R'Judah and R'Simeon the halachah is in agreement with R'Judah'?<span class="x" onmousemove="('comment',' Of course it has. Hence R. Mesharsheya's conclusion that the rules as to the halachah are to be disregarded.');">⁵</span> - What, however, is really the difficulty?

Jastrow