scholarly journals Tight lower bounds for the longest common extension problem

2017 ◽  
Vol 125 ◽  
pp. 26-29
Author(s):  
Dmitry Kosolobov
2015 ◽  
Vol 48 (1) ◽  
Author(s):  
Jan Spaliński

AbstractA duchain complex of W. Dwyer and D. Kan is a common extension of the notions of a chain complex and a cochain complex.Given a square commutative diagram of duchain complexes, the lifting-extension problem asks whether there exists a diagonal map making the two resulting triangles commute. Duchain complexes have a model category structure, and hence a lift exists if the left vertical map is a cofibration, the right vertical map is a fibration, and one of them is a weak equivalence.We show that it is possible to replace the two conditions above, by a countably infinite, bigraded, family of conditions which guarantee the existence of a lift.


Author(s):  
Parinya CHALERMSOOK ◽  
Hiroshi IMAI ◽  
Vorapong SUPPAKITPAISARN

2020 ◽  
Vol 148 (2) ◽  
pp. 321-327
Author(s):  
Rodolfo Gutiérrez-Romo ◽  
Carlos Matheus
Keyword(s):  

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