3 papers
math.CO2026
-weight system does not extend to a graph 4-invariant
Daniil Fomichev, Maksim Karev, Fedor Pavutnitskiy +1
A long-standing question by S. Lando asks whether the -weight system extends to a unique 4-invariant of graphs. We show that, in full generality, the answer to th…
math.KT2024
Limits via relations
Sergei O. Ivanov, Roman Mikhailov, Fedor Pavutnitskiy
In this paper, we study operations on functors in the category of abelian groups simplar to the derivation in the sense of Dold-Puppe. They are defined as derived limits of a funct…
math.GR2019
Limits, standard complexes and fr-codes
Sergei O. Ivanov, Roman Mikhailov, Fedor Pavutnitskiy
For a strongly connected category with pair-wise coproducts, we introduce a cosimplicial object, which serves as a sort of resolution for computing higher derived func…