Results 71 to 80 of about 17,323 (202)

On separable extensions of group rings and quaternion rings

International Journal of Mathematics and Mathematical Sciences, 1978
The purposes of the present paper are (1) to give a necessary and sufficient condition for the uniqueness of the separable idempotent for a separable group ring extension RG(R may be a non-commutative ring), and (2) to give a full description of the set ...
George Szeto
doaj   +1 more source

Threads without idempotents [PDF]

Proceedings of the American Mathematical Society, 1961
If a thread S has no idempotents and if S2 = S, then S is iseomorphic with the real interval (0, 1) under ordinary multiplication [2, Corollary 5.6]. Although the result is not nearly as pleasing as the special case just quoted, we shall give here a description of any thread without idempotents.
openaire   +1 more source

On cohomology of locally profinite sets

Proceedings of the London Mathematical Society, Volume 132, Issue 5, May 2026.
Abstract We construct a locally profinite set of cardinality ℵω$\aleph _{\omega }$ with infinitely many first cohomology classes of which any distinct finite product does not vanish. Building on this, we construct the first example of a nondescendable faithfully flat map between commutative rings of cardinality ℵω$\aleph _{\omega }$ within Zermelo ...
Ko Aoki
wiley   +1 more source

Decomposition of Idempotent Operators on Hilbert C*-Modules

Mathematics
This study advances the application of the generalized Halmos’ two projections theorem to idempotent operators on Hilbert C*-modules through a comprehensive study of sums involving adjointable idempotents and their adjoints.
Wei Luo
doaj   +1 more source

Idempotent Noether lattices [PDF]

Proceedings of the American Mathematical Society, 1969
In his paper, Abstract commutative ideal theory [2 ], Dilworth proved that a Noether lattice on which the multiplication is the meet operation is a finite Boolean algebra. This note proves that if the multiplication in a Noether lattice is idempotent (A2= A for all A in the lattice), then the lattice is a finite Boolean algebra.
openaire   +2 more sources

Recursive and Cyclic Constructions for Double‐Change Covering Designs

Journal of Combinatorial Designs, Volume 34, Issue 4, Page 198-209, April 2026.
ABSTRACT A double‐change covering design (DCCD) is a v‐set V and an ordered list L of b blocks of size k where every pair from V must occur in at least one block and each pair of consecutive blocks differs by exactly two elements. It is minimal if it has the fewest blocks possible and circular when the first and last blocks also differ by two elements.
Amanda Lynn Chafee, Brett Stevens
wiley   +1 more source

Corpidi e loro proprietà

Le Matematiche, 2009
A corpid is a ring (K, +, ·), different from zero, such that (K, ·) is an inverse semigroup. We prove a characterization of corpids, some remarkable results about the lattice of the idempotents and other results concerning the idempotents and the zero ...
Maria Scafati Tallini, Maurizio Iurlo
doaj  

On the existence of idempotent liftings [PDF]

Proceedings of the American Mathematical Society, 1989
An existence theorem for idempotent liftings is proved. This implies that every compact measure space with full support and separable measure algebra admits an idempotent lifting.
openaire   +2 more sources

Tessellation Groups, Harmonic Analysis on Non‐Compact Symmetric Spaces and the Heat Kernel in View of Cartan Convolutional Neural networks

Fortschritte der Physik, Volume 74, Issue 4, April 2026.
ABSTRACT In this paper, we continue the development of the Cartan neural networks programme, launched with three previous publications, by focusing on some mathematical foundational aspects that we deem necessary for our next steps forward. The mathematical and conceptual results are diverse and span various mathematical fields, but the inspiring ...
Pietro Fré, Federico Milanesio, Marcelo Oyarzo, Matteo Santoro, Mario Trigiante   +4 more
wiley   +1 more source

Amitsur's theorem, semicentral idempotents, and additively idempotent semirings

Open Mathematics
The article explores research findings akin to Amitsur’s theorem, asserting that any derivation within a matrix ring can be expressed as the sum of an inner derivation and a hereditary derivation.
Rachev Martin, Trendafilov Ivan
doaj   +1 more source