Ng's conjecture relating abelian contact homology to the branched-cover character ring

Let KK be a knot in bS3bS^3, let bbSigmad2KbbSigmad_2K be its 2-fold branched covering, and let X(bbSigmad2K)X(bbSigmad_2K) be the bSL2(bC)bSL_2(bC) character variety of bpi1(bbSigmad2K)bpi_1(bbSigmad_2K). Write aija_{ij} for the generators of the degree-zero abelian contact homology algebra HC0ab(K)HC_0^{ab}(K) and zij=tr(ρ(mimj))z_{ij}=\operatorname{tr}(\rho(m_im_j)) for the corresponding coordinate functions on X(bbSigmad2K)X(bbSigmad_2K). Ng's conjecture. For any knot KK, the homomorphism

g:HC0ab(K)bCbC[X(bbSigmad2K)]g: HC_0^{ab}(K) \otimes bC \longrightarrow bC[X(bbSigmad_2K)]

defined by g(aij)=zijg(a_{ij})=-z_{ij} (1i<jn)(1\leq i<j\leq n) and g(1)=1g(1)=1 gives an isomorphism. In particular, HC0ab(K)\otimesbCHC_0^{ab}(K)\otimesbC and bC[X(bbSigmad2K)]bC[X(bbSigmad_2K)] are isomorphic. This conjecture proposes that the abelianized degree-zero contact homology detects the coordinate ring of the character variety of the 2-fold branched cover for every knot; its resolution is not supplied here.

Sources & referencesView supporting material

Primary source

Fumikazu Nagasato and Shinnosuke Suzuki, “Trace-free characters and abelian knot contact homology II”, arXiv:1708.00874 (2026).

Additional references

2 papers in this index state this conjecture (2017). The statement above is taken from the most recent of them; the others are arXiv:1708.00851.

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.