Abstract
If \(i:A\subset B\) is a commutative ring extension, we show that the group \({\mathcal I}(A,B)\) of invertible A-submodules of B is contracted in the sense of Bass, with \(L{\mathcal I}(A,B)=H^0_{\mathrm {et}}(A,i_*{\mathbb Z}/{\mathbb Z})\). This gives a canonical decomposition for \({\mathcal I}(A[t,\frac{1}{t}],B[t,\frac{1}{t}])\).
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Acknowledgments
The first author would like to express his sincere thanks to Balwant Singh for many fruitful discussions and for his guidance, and to D. S. Nagaraj for useful discussion.
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Sadhu was supported by IMSC, Chennai Postdoctoral Fellowship.
Weibel was supported by NSF grants.
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Sadhu, V., Weibel, C. Relative Cartier divisors and Laurent polynomial extensions. Math. Z. 285, 353–366 (2017). https://doi.org/10.1007/s00209-016-1710-1
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DOI: https://doi.org/10.1007/s00209-016-1710-1