def _coerce_map_from_(self, R): """ Finds coercion maps from R to this ring. EXAMPLES:: sage: R = Zp(5); S.<x> = ZZ[]; f = x^5 + 25*x - 5; W.<w> = R.ext(f) sage: L = W.fraction_field() sage: w + L(w) #indirect doctest 2*w + O(w^101) sage: w + R(5,2) w + w^5 + O(w^10) """ # Far more functionality needs to be added here later. if isinstance(R, pAdicExtensionGeneric) and R.fraction_field() is self: if self._implementation == 'NTL': return True elif R._prec_type() == 'capped-abs': from sage.rings.padics.qadic_flint_CA import pAdicCoercion_CA_frac_field as coerce_map elif R._prec_type() == 'capped-rel': from sage.rings.padics.qadic_flint_CR import pAdicCoercion_CR_frac_field as coerce_map elif R._prec_type() == 'floating-point': from sage.rings.padics.qadic_flint_FP import pAdicCoercion_FP_frac_field as coerce_map elif R._prec_type() == 'fixed-mod': from sage.rings.padics.qadic_flint_FM import pAdicCoercion_FM_frac_field as coerce_map return coerce_map(R, self)