# Singular

## News for version 4-1-1

New syntax:

• `alias`: may be used as a prefix to a variable declaration. Can only be used in procedure headings. ( General command syntax).

New command:

• `fres`: improved version of `sres`: computes a (not necessarily minimal) free resolution of the input ideal/module, using Schreyer's algorithm. ( fres, sres).

Extended commands:

• pseudo ordering `L` allows setting of limits for exponents in polynomials ( Pseudo ordering L, attrib for `maxExp`)
• `%`,`mod`: also for poly operands ( poly operations).
• `delete`: extended to intvec, ideal, module ( delete).
• syz ( syz), lift ( lift), liftstd ( liftstd), intersect( intersect): with a specified GB algorithm

New libraries:

• classify2.lib: Classification of isolated singularities of corank <=2 and modality <= wrt. right equivalence over the complex numbers according to Arnold's list. ( classify2_lib)
• goettsche.lib: Goettsche's formula for the Betti numbers of the Hilbert scheme of points on a surface, Macdonald's formula for the symmetric product ( goettsche_lib)
• combinat.lib, modules.lib, methods,lib, nets.lib: a more mathematical view of modules ( combinat_lib: combinatorics), ( methods_lib: construct procedures), ( modules_lib: free resolutions), ( nets_lib: pretty printing)
• ncHilb.lib: Hilbert series of non-commutative monomial algebras ( ncHilb_lib)
• realclassify.lib: Classification of real singularities( realclassify_lib)
• rootisolation.lib: real root isolation using interval arithmetic( rootisolation_lib)
• rstandard.lib: Janet bases and border bases for ideals ( rstandard_lib)

Changed libraries:

Changes in the kernel/build system:

• port to polymake 3.x.x
• port to NTL 10 with threads (needs also C++11: gcc6 or -std=c++11)
• p_Invers is only a helper for p_Series: now static
• p_Divide is now p_MDivide, pDivive is a new routine