Baer’s criterion helps to identify the injective objects in a category of modules by reducing the problem of map extension to a certain subclass of morphisms. Due to its notorious reliance on Zorn’s lemma, it is inherently non-constructive. However, we put Baer’s criterion on constructive grounds by couching it in point-free terms. Classical principles which will be developed alongside readily allow to gain back the conventional version. Several case studies further indicate a fair applicability.
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Keywords: Injective module, Baer’s criterion, point-free topology, inductive definition, constructive algebra
Daniel Misselbeck-Wessel 1; Davide Rinaldi 
@article{CML_2022__14_1_49_0, author = {Daniel Misselbeck-Wessel and Davide Rinaldi}, title = {Towards formal {Baer} criteria}, journal = {Confluentes Mathematici}, pages = {49--63}, publisher = {Institut Camille Jordan}, volume = {14}, number = {1}, year = {2022}, doi = {10.5802/cml.82}, language = {en}, url = {https://cml.centre-mersenne.org/articles/10.5802/cml.82/} }
TY - JOUR AU - Daniel Misselbeck-Wessel AU - Davide Rinaldi TI - Towards formal Baer criteria JO - Confluentes Mathematici PY - 2022 SP - 49 EP - 63 VL - 14 IS - 1 PB - Institut Camille Jordan UR - https://cml.centre-mersenne.org/articles/10.5802/cml.82/ DO - 10.5802/cml.82 LA - en ID - CML_2022__14_1_49_0 ER -
Daniel Misselbeck-Wessel; Davide Rinaldi. Towards formal Baer criteria. Confluentes Mathematici, Volume 14 (2022) no. 1, pp. 49-63. doi : 10.5802/cml.82. https://cml.centre-mersenne.org/articles/10.5802/cml.82/
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