Related for Taanit 59:3
ואי אשמועינן הלכה כרשב"ג הוה אמינא אפילו לאחריו קמ"ל הלכה כרבי מאיר:
For had it only been stated that the halachah is according to R'Meir, I might have said that the restriction is in force from the beginning of the month, therefore it is also clearly stated that the halachah is according to R'Simeon B'Gamaliel; and had it only been stated that the halachah is according to R'Simeon B'Gamaliel, I would have said that the restriction continues even on the days after [the Ninth of Ab], therefore it is clearly state that the halachah is according to R'Meir.<span class="x" onmousemove="('comment',' Who is opposed to the view.');"><sup>4</sup></span> ON THE EVE OF THE NINTH OF AB ONE MAY NOT PARTAKE OF A MEAL OF TWO COURSES etc. Rab Judah said: This restriction applies to any time after midday<span class="x" onmousemove="('comment',' Lit., 'from the sixth hour onward'.');"><sup>5</sup></span> but not to any time before midday.