{ "id": "1903.08996", "version": "v1", "published": "2019-03-20T12:56:22.000Z", "updated": "2019-03-20T12:56:22.000Z", "title": "A zig-zag conjecture and local constancy for Galois representations", "authors": [ "Eknath Ghate" ], "comment": "arXiv admin note: text overlap with arXiv:1901.01728", "categories": [ "math.NT" ], "abstract": "We make a zig-zag conjecture describing the reductions of irreducible crystalline two-dimensional representations of $G_{{\\mathbb{Q}}_p}$ of half-integral slopes and exceptional weights. Such weights are two more than twice the slope mod $(p-1)$. We show that zig-zag holds for half-integral slopes at most $\\frac{3}{2}$. We then explore the connection between zig-zag and local constancy results in the weight. First we show that known cases of zig-zag force local constancy to fail for small weights. Conversely, we explain how local constancy forces zig-zag to fail for some small weights and half-integral slopes at least $2$. However, we expect zig-zag to be qualitatively true in general. We end with some compatibility results between zig-zag and other results.", "revisions": [ { "version": "v1", "updated": "2019-03-20T12:56:22.000Z" } ], "analyses": { "keywords": [ "zig-zag conjecture", "galois representations", "half-integral slopes", "zig-zag force local constancy", "local constancy forces zig-zag" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }