29 citations · 52 across the 15 of their papers we have counts for
17 papers
Intrinsic tensor products and a Ganea-type extension of the five-term exact sequence
Bo Shan Deval, Manfred Hartl, Tim Van der Linden
We define an intrinsic symmetric bi-right-exact (and for varieties, bi-cocontinuous) bilinear product on objects of a semi-abelian category, constructed as the cosmash product in t…
A formula for the second cohomology of two-step nilpotent groups
Karel Dekimpe, Manfred Hartl, Sarah Wauters
In [5], the notion of polynomial cocycles is used to give an expression for the second cohomology of T-groups with coefficients in a torsion-free nilpotent module. We make this exp…
Polynomial functors from Algebras over a set-operad and non-linear Mackey functors
Manfred Hartl, Teimuraz Pirashvili, Christine Vespa
In this paper, we give a description of polynomial functors from (finitely generated free) groups to abelian groups in terms of non-linear Mackey functors generalizing those given…
An explicit seven-term exact sequence for the cohomology of a Lie algebra extension
Karel Dekimpe, Manfred Hartl, Sarah Wauters
We construct a seven-term exact sequence involving low degree cohomology spaces of a Lie algebra $\Lg$, an ideal $\Lh$ of $\Lg$ and the quotient $\Lg / \Lh$ with coefficients in a…
The ternary commutator obstruction for internal crossed modules
Manfred Hartl, Tim Van der Linden
In finitely cocomplete homological categories, co-smash products give rise to (possibly higher-order) commutators of subobjects. We use binary and ternary co-smash products and the…
A seven-term exact sequence for the cohomology of a group extension
Karel Dekimpe, Manfred Hartl, Sarah Wauters
In this paper, we construct a seven-term exact sequence involving the cohomology groups of a group extension. Although the existence of such a sequence can be derived using spectra…