English

A Torelli type theorem for exp-algebraic curves

Complex Variables 2018-05-29 v2

Abstract

An exp-algebraic curve consists of a compact Riemann surface SS together with nn equivalence classes of germs of meromorphic functions modulo germs of holomorphic functions, \HH={[h1],,[hn]}\HH = \{ [h_1], \cdots, [h_n] \}, with poles of orders d1,,dn1d_1, \cdots, d_n \geq 1 at points p1,,pnp_1, \cdots, p_n. This data determines a space of functions \OO\HH\OO_{\HH} (respectively, a space of 11-forms Ω\HH0\Omega^0_{\HH}) holomorphic on the punctured surface S=S{p1,,pn}S' = S - \{p_1, \cdots, p_n\} with exponential singularities at the points p1,,pnp_1, \cdots, p_n of types [h1],,[hn][h_1], \cdots, [h_n], i.e., near pip_i any f\OO\HHf \in \OO_{\HH} is of the form f=gehif = ge^{h_i} for some germ of meromorphic function gg (respectively, any ωΩ\HH0\omega \in \Omega^0_{\HH} is of the form ω=αehi\omega = \alpha e^{h_i} for some germ of meromorphic 11-form). For any ωΩ\HH0\omega \in \Omega^0_{\HH} the completion of SS' with respect to the flat metric ω|\omega| gives a space S=S\RRS^* = S' \cup \RR obtained by adding a finite set \RR\RR of idi\sum_i d_i points, and it is known that integration along curves produces a nondegenerate pairing of the relative homology H1(S,\RR;\C)H_1(S^*, \RR ; \C) with the deRham cohomology group defined by HdR1(S,\HH):=Ω\HH0/d\OO\HHH^1_{dR}(S, \HH) := \Omega^0_{\HH}/d\OO_{\HH}. There is a degree zero line bundle L\HHL_{\HH} associated to an exp-algebraic curve, with a natural isomorphism between Ω\HH0\Omega^0_{\HH} and the space W\HHW_{\HH} of meromorphic L\HHL_{\HH}-valued 11-forms which are holomorphic on SS', so that H1(S,\RR;\C)H_1(S^*, \RR ; \C) maps to a subspace K\HHW\HHK_{\HH} \subset W^*_{\HH}. We show that the exp-algebraic curve (S,\HH)(S, \HH) is determined uniquely by the pair (L\HH,K\HHW\HH)(L_{\HH},\, K_{\HH} \subset W^*_{\HH}).

Keywords

Cite

@article{arxiv.1606.06449,
  title  = {A Torelli type theorem for exp-algebraic curves},
  author = {Indranil Biswas and Kingshook Biswas},
  journal= {arXiv preprint arXiv:1606.06449},
  year   = {2018}
}

Comments

arXiv admin note: substantial text overlap with arXiv:1602.08219

R2 v1 2026-06-22T14:30:08.778Z