We study the theory of lovely pairs of geometric structures, in particular o-minimal structures. We characterize "linear" theories in terms of properties of the correspon...
We show analogues of a theorem due to Valiant and Vazirani [16] for intractable parameterized complexity classes such as W[P], W[SAT] and the classes of the W-hierarchy as well as...
Sylvester’s identity is a classical determinantal identity with a straightforward linear algebra proof. We present combinatorial proofs of several non-commutative extensions, an...
We use a generalization of Wiener's 1/f theorem to prove that for a Gabor frame with the generator in the Wiener amalgam space W (L , 1 )(Rd ), the corresponding frame operato...
We compare two Picard groups in dimension one. Our proofs are constructive and the results generalize a theorem of J. Sands [11]. MSC 2000: 13C15, 13C20, 03F65, 13F45