- new packages:
- BinomialEdgeIdeals, a package by Tobias Windisch for computations with binomial edge ideals, has been added.
- TateOnProducts, a package by Daniel Erman, David Eisenbud, and Frank-Olaf Schreyer for Tate resolutions on products of projective spaces, has been added.
- LatticePolytopes, a package by Anders Lundman and Gustav Sædén Ståhl for computations with lattice polytopes, has been added.
- FiniteFittingIdeals, a package by Gustav Sædén Ståhl for computing Fitting ideals of finite modules, has been added.
- HigherCIOperators, a package by David Eisenbud for computing higher complete intersection operators, has been added. It implements some work of Burke, Eisenbud and Schreyer on a structure that exists on resolutions over a complete intersection. This structure allows one to
*lift*a resolution over a complete intersection to a resolution over the ambient ring -— a construction dual, in a sense, to the well known Eisenbud-Shamash construction, which is also implemented. - LieTypes, a package by Dave Swinarski for defining types used by the package ConformalBlocks, has been added.
- ConformalBlocks, a package by Dave Swinarski for computing ranks and first Chern classes of conformal block bundles on the moduli space of n-pointed curves of genus 0, has been added.
- M0nbar, a package by Han-Bom Moon and David Swinarski for calculations for divisors and F-curves on the moduli space of stable n-pointed genus zero curves, has been added.
- AnalyzeSheafOnP1, a package by David Eisenbud for decomposing a coherent sheaf on the projective line into a direct sum of line bundles and cyclic skyscraper sheaves, has been added.

- improved packages:
- The package Binomials has been upgraded from version 1.0 to 1.2.
- The package BoijSoederberg has been upgraded from version 1.2 to 1.5.
- The package ChainComplexExtras has been upgraded from version 0.5 to version 1.
- The package MultiplierIdeals has been upgraded from version 1.0 to version 1.1.
- The package CompleteIntersectionResolutions has been upgraded from version 0.8 to version 0.9. It implements a number of old and new ideas about minimal resolutions over a complete intersection developed by Eisenbud-Peeva, Avramov-Jorgensen, Eisenbud-Peeva-Schreyer, and Burke-Eisenbud-Schreyer. Let
`S = k[x_1..x_n]`be a polynomial ring, ff a codimension c regular sequence of homogeneous forms of the same degree, and`R = S/(ff)`. It contains:- routines to compute the structure of
*higher matrix factorization*on a*high*R-syzygy M — one for which the modules`Ext_R^even(M,k)`and`Ext_R^odd(M,k)`have negative regularity over the ring of CI operators. There are also routines to extract various information from the higher matrix factorization. - routines that implement the reconstruction algorithm of Avramov and Jorgensen that constructs modules M having (certain kinds of) specified Ext-modules.
- routines to test of a conjecture of Eisenbud about the vanishing of certain local cohomology of Ext-modules, implementing the map from a module to its saturation.
- routines to compute the higher homotopies for ff on an S-free resolution of an S-module M annihilated by ff, and understanding the structure of module over an exterior algebra, determined by the ff-homotopies on a resolution of M, on Tor^S(M,N) and Ext_S(M,N), when M and N are S-modules annihilated by ff. These routines led to conjectures that were later proven, and will appear in a work-in-progress of Eisenbud, Peeva and Schreyer.
- routines to compute Hom in the stable category of Cohen-Macaulay R-modules, and test for stable triviality. This is used in understanding possible obstructions to commutativity of CI-operators.

- routines to compute the structure of

- functionality added or improved:
- The function pairs will now accept (basic) list (or sequence)
`x`and return the list of pairs`(i,x#i)`, thanks to Zach Teitler. - The function minimalPresentation has been modified so that it applies its degree-preserving method also for homogeneous modules over affine algebras over affine algebras.
- The function applyKeys will now accept an additional function to be called when collisions occur between new keys, for combining the corresponding values, thanks to Paul Zinn-Justin.
- The function partition now takes a third argument: a list of additional values in the range of the function, allowing members of the resulting partition to be empty.
- The function loadPackage can now be used to reload a package by giving the package itself as the argument. This is easier than setting the Reload option.
- The function adjoint has been improved to work not just for free modules, and the function
`adjoint1`has been replaced by adjoint'. This pair of function now implements both direction in the adjointness between Hom and tensor product. - The new function homomorphism' complements homomorphism. From a map between modules it produces the element of Hom.
- The new function compose expresses composition of maps between modules as a bilinear map between Hom-modules.
- Bracket powers of ideals (
`(symbol ^,Ideal,Array)`(missing documentation)) have been added, thanks to Frank Moore. - Several bugs related to computing Groebner bases in polynomial rings over ZZ have been fixed.
`trim I`in this case now returns an ideal or module with a Groebner basis as generating set, as a minimal generating set isn't well-defined. In a future release, we hope to provide a function to determine a smaller set of generators.`mingens I`also returns the Groebner basis matrix. In a future release this function might be changed to give an error in cases where there is not a well-defined notion of minimal generators.

- The function pairs will now accept (basic) list (or sequence)
- functionality changed:
- The function export now accepts strings and options only, not symbols.