On the group of extensions Ext1($\mathscr{G}$(λ0), $\mathscr{E}$(λ1, ..., λ n )) over a discrete valuation ring
Kondo, Takashi
Tsukuba J. Math., Tome 34 (2011) no. 2, p. 265-294 / Harvested from Project Euclid
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For given group schemes $\mathscr{G}$(λ i ) (i = 1, 2, ...) deforming the additive group scheme G a to the multiplicative group scheme G m , T. Sekiguchi and N. Suwa constructed extensions: 0 → $\mathscr{G}$(λ2) → $\mathscr{E}$(λ1, λ2) → $\mathscr{G}$(λ1) → 0, … 0 → $\mathscr{G}$(λ n ) → $\mathscr{E}$(λ1, ..., λ n ) → $\mathscr{E}$(λ1, ..., λn-1) → 0, … inductively, by calculating the group of extensions Ext1($\mathscr{E}$(λ1, ..., λn-1), $\mathscr{G}$(λ n )). Here changing the group schemes, we treat the group Ext1($\mathscr{G}$(λ0), $\mathscr{E}$(λ1, ..., λ n )) of extensions for any positive integers n. The case of n = 2, 3 were studied by D. Horikawa and T. Kondo.
Publié le : 2011-02-15
Classification:  
@article{1302268249,
     author = {Kondo, Takashi},
     title = {On the group of extensions
 Ext<sup>1</sup>($\mathscr{G}$<sup>($\lambda$<sub>0</sub>)</sup>,
 $\mathscr{E}$<sup>($\lambda$<sub>1</sub>, ..., $\lambda$<sub>
 n
 </sub>)</sup>) over a discrete valuation ring},
     journal = {Tsukuba J. Math.},
     volume = {34},
     number = {2},
     year = {2011},
     pages = { 265-294},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1302268249}
}

Kondo, Takashi. On the group of extensions
 Ext1($\mathscr{G}$(λ0),
 $\mathscr{E}$(λ1, ..., λ
 n
 )) over a discrete valuation ring. Tsukuba J. Math., Tome 34 (2011) no. 2, pp.  265-294. http://gdmltest.u-ga.fr/item/1302268249/