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Degree estimate for subalgebras generated by two elements

Leonid Makar-Limanov, Jie-Tai Yu (2008)

Journal of the European Mathematical Society

We develop a new combinatorial method to deal with a degree estimate for subalgebras generated by two elements in different environments. We obtain a lower bound for the degree of the elements in two-generated subalgebras of a free associative algebra over a field of zero characteristic. We also reproduce a somewhat refined degree estimate of Shestakov and Umirbaev for the polynomial algebra, which plays an essential role in the recent celebrated solution of the Nagata conjecture and the strong...

Derivations with Engel conditions in prime and semiprime rings

Shuliang Huang (2011)

Czechoslovak Mathematical Journal

Let R be a prime ring, I a nonzero ideal of R , d a derivation of R and m , n fixed positive integers. (i) If ( d [ x , y ] ) m = [ x , y ] n for all x , y I , then R is commutative. (ii) If Char R 2 and [ d ( x ) , d ( y ) ] m = [ x , y ] n for all x , y I , then R is commutative. Moreover, we also examine the case when R is a semiprime ring.

Derivations with power central values on Lie ideals in prime rings

Basudeb Dhara, Rajendra K. Sharma (2008)

Czechoslovak Mathematical Journal

Let R be a prime ring of char R 2 with a nonzero derivation d and let U be its noncentral Lie ideal. If for some fixed integers n 1 0 , n 2 0 , n 3 0 , ( u n 1 [ d ( u ) , u ] u n 2 ) n 3 Z ( R ) for all u U , then R satisfies S 4 , the standard identity in four variables.

Derived dimension via τ -tilting theory

Yingying Zhang (2021)

Czechoslovak Mathematical Journal

Comparing the bounded derived categories of an algebra and of the endomorphism algebra of a given support τ -tilting module, we find a relation between the derived dimensions of an algebra and of the endomorphism algebra of a given τ -tilting module.

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