TT #694 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:06
And it shall be that the firstborn that she bears shall succeed to the name of his dead brother, so that his name shall not be blotted out from Israel.
Torah Temimah points to Yevamot 40a.
TT lemma: יָקוּם עַל שֵׁם אָחִיו.
הָאִשָּׁה שֶׁאָמְרָה מֵת בַּעְלִי וְנִתְיַבְּמָה – יְבָמָהּ נִכְנָס לַנַּחֲלָה עַל פִּיהָ, דִּכְתִיב יָקוּם עַל שֵׁם אָחִיו וְהֲרֵי קָם.
English: A woman who said “my husband is dead” and was taken in yibbum — her yavam enters into the inheritance on the strength of her word, for it is written “he shall succeed to the name of his brother” — and he has succeeded.
On the daf / in context: Unlike ordinary inheritance (which requires clear evidence), the yavam’s acquisition follows the same leniency granted for the woman’s remarriage.
Derash extending the woman’s testimony to the inheritance effect.
When a woman is believed to say her husband died and is taken in yibbum, the yavam also acquires the inheritance share on the basis of her testimony.