{ "id": "2301.09847", "version": "v1", "published": "2023-01-24T07:11:54.000Z", "updated": "2023-01-24T07:11:54.000Z", "title": "Non-degeneracy results for (multi-)pushouts of compact groups", "authors": [ "Alexandru Chirvasitu" ], "comment": "24 pages + references", "categories": [ "math.GR", "math.CT", "math.GN", "math.RT" ], "abstract": "We prove that embeddings of compact groups are equalizers, and a number of results on pushouts (and more generally, amalgamated free products) in the category of compact groups. Call a family of compact-group embeddings $H\\le G_i$ {\\it algebraically sound} if the corresponding group-theoretic pushout embeds in its Bohr compactification. We (a) show that a family of normal embeddings is algebraically sound in the sense that $G_i$ admit embeddings $G_i\\le G$ into a compact group which agree on $H$; (b) give equivalent characterizations of coherently embeddable families of normal embeddings in representation-theoretic terms, via Clifford theory; (c) characterize those compact connected Lie groups $H$ for which all finite families of normal embeddings $H\\trianglelefteq G_i$ are coherently embeddable as those whose centers do not contain 2-tori, and (d) show that families of {\\it split} embeddings of compact groups are always algebraically sound.", "revisions": [ { "version": "v1", "updated": "2023-01-24T07:11:54.000Z" } ], "analyses": { "subjects": [ "22C05", "18A30", "22A05", "18A20", "22E46", "22D10", "54A10" ], "keywords": [ "compact group", "non-degeneracy results", "normal embeddings", "algebraically sound", "corresponding group-theoretic pushout embeds" ], "note": { "typesetting": "TeX", "pages": 24, "language": "en", "license": "arXiv", "status": "editable" } } }