Let $\Lambda $ be a finite dimensional algebra with an action by a finite group $G$ and $A:= \Lambda *G$ the skew group algebra. One of our main results asserts that the canonical restriction-induction adjoint pair induced by the skew group algebra extension $\Lambda \subset A$ induces a poset isomorphism between the poset of $G$-stable support $\tau $-tilting modules over $\Lambda $ and that of ($\operatorname{mod}G$)-stable support $\tau $-tilting modules over $A$. We also establish a similar poset isomorphism between posets of appropriate classes of silting complexes over $\Lambda $ and $A$. These two results generalize and unify the preceding results by Zhang–Huang, Breaz–Marcus–Modoi and the second and the third authors. Moreover, we give a practical condition under which $\tau $-tilting finiteness and silting discreteness of $\Lambda $ are inherited by $A$. As applications we study $\tau $-tilting theory and silting theory of the (generalized) preprojective algebras and the folded mesh algebras. Among other things, we determine the posets of support $\tau $-tilting modules and of silting complexes over preprojective algebra $\Pi (\mathbb{L}_{n})$ of type $\mathbb{L}_{n}$.
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Keywords: $\tau $-tilting theory, silting complexes, skew group algebras
Kimura, Yuta 1; Koshio, Ryotaro 2; Kozakai, Yuta 3; Minamoto, Hiroyuki 4; Mizuno, Yuya 5

@article{ART_2025__2_4_599_0, author = {Kimura, Yuta and Koshio, Ryotaro and Kozakai, Yuta and Minamoto, Hiroyuki and Mizuno, Yuya}, title = {$\tau $-tilting theory and silting theory of skew group algebra extensions}, journal = {Annals of Representation Theory}, pages = {599--637}, publisher = {The Publishers of ART}, volume = {2}, number = {4}, year = {2025}, doi = {10.5802/art.31}, language = {en}, url = {https://art.centre-mersenne.org/articles/10.5802/art.31/} }
TY - JOUR AU - Kimura, Yuta AU - Koshio, Ryotaro AU - Kozakai, Yuta AU - Minamoto, Hiroyuki AU - Mizuno, Yuya TI - $\tau $-tilting theory and silting theory of skew group algebra extensions JO - Annals of Representation Theory PY - 2025 SP - 599 EP - 637 VL - 2 IS - 4 PB - The Publishers of ART UR - https://art.centre-mersenne.org/articles/10.5802/art.31/ DO - 10.5802/art.31 LA - en ID - ART_2025__2_4_599_0 ER -
%0 Journal Article %A Kimura, Yuta %A Koshio, Ryotaro %A Kozakai, Yuta %A Minamoto, Hiroyuki %A Mizuno, Yuya %T $\tau $-tilting theory and silting theory of skew group algebra extensions %J Annals of Representation Theory %D 2025 %P 599-637 %V 2 %N 4 %I The Publishers of ART %U https://art.centre-mersenne.org/articles/10.5802/art.31/ %R 10.5802/art.31 %G en %F ART_2025__2_4_599_0
Kimura, Yuta; Koshio, Ryotaro; Kozakai, Yuta; Minamoto, Hiroyuki; Mizuno, Yuya. $\tau $-tilting theory and silting theory of skew group algebra extensions. Annals of Representation Theory, Volume 2 (2025) no. 4, pp. 599-637. doi : 10.5802/art.31. https://art.centre-mersenne.org/articles/10.5802/art.31/
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