The PresRing type contains about a Subring instance is related to the lifted presentation ring of a subring. In the code, the lifted presentation of a subring is referred to as the tensorRing.
An instance of the PresRing type contains the following keys:
To understand the maps stored inside of a PresRing instance, it is informative to look at the output of debugPrintAllMaps:
i1 : gndR = QQ[x, y]; |
i2 : subR = subring {y, y*x-x^2, y*x^2}; |
i3 : debugPrintAllMaps subR - sagbiInclusion: maps p_0 to 0 maps p_1 to 0 maps p_2 to p_2 maps p_3 to p_3 maps p_4 to p_4 - projectionAmbient: maps p_0 to x maps p_1 to y maps p_2 to 0 maps p_3 to 0 maps p_4 to 0 - inclusionAmbient: maps x to p_0 maps y to p_1 - substitution: maps p_0 to p_0 maps p_1 to p_1 maps p_2 to p_1 maps p_3 to -p_0^2+p_0*p_1 maps p_4 to p_0^2*p_1 - fullSubstitution: maps p_0 to x maps p_1 to y maps p_2 to y maps p_3 to -x^2+x*y maps p_4 to x^2*y |
This type is typically not used externally to Subring type.