We study the robustness of quantum computers under the influence of errors modelled by strictly contractive channels. A channel T is defined to be strictly contractive if, for any pair of density operators ρ, σ in its domain, ‖Tρ− Tσ‖1 ≤ k ‖ρ− σ‖1 for some 0 ≤ k < 1 (here ‖·‖1 denotes the trace norm). In other words, strictly contractive channels render the states of the computer less distingui...

Important problems in wireless networks can often be solved by computing fixed points of standard or contractive interference mappings, and the conventional fixed point algorithm is widely used for this purpose. Knowing that the mapping used in the algorithm is not only standard but also contractive (or only contractive) is valuable information because we obtain a guarantee of geometric converg...

We show that every logmodular subalgebra of Mn(C) is unitary equivalent to an algebra of block upper triangular matrices, which was conjectured in [5]. In particular, this shows that every unital contractive representation of a logmodular subalgebra of Mn(C) is automatically completely contractive.

A new method is given to optimize parameters of a dynamical model by supplementing the conventional methods with a contractive mapping procedure. Numerical results indicate that the present method is more efficient than conventional methods. Key-Words: Parameter optimization; Contractive mapping; Complexity

In this paper, we establish some common fixed point theorems for fuzzy mappings satisfying fuzzy contractive conditions which are general than Chatterjee type and Kannan type fuzzy contractive conditions on closed balls in a complete metric space. Our results generalize the corresponding results in the current literature. AMS (2000) subject classification: 45S40 • 47H10 • 54H25

We prove results concerning data dependence of Noor and SP iterative schemes using certain quasi-contractive operators in real Banach spaces. Our results reveal that by choosing an approximate quasi-contractive operator (for which it is possible to compute the fixed point); we can approximate the fixed point of the given operator. An example is also provided to explain the validity of our results.

We prove that for any infinite field F , the map H3(SLn(F ), Z)→ H3(SLn+1(F ), Z) is an isomorphism for all n ≥ 3. When n = 2 the cokernel of this map is naturally isomorphic to 2 · K 3 (F ), where K n (F ) is the nth Milnor K-group of F . We deduce that the natural homomorphism from H3(SL2(F ), Z) to the indecomposable K3 of F , K3(F ), is surjective for any infinite field F .

Using the setting of generalized metric space, the so-called G-metric space, fixed point theorems for mappings with a contractive and a generalized contractive iterate at a point are proved. These results generalize some comparable results in the literature. A common fixed point result is also proved.

in the present paper, we introduces the notion of integral type contractive mapping with respect to ordered s-metric space and prove some coupled common fixed point results of integral type contractive mapping in ordered s-metric space. moreover, we give an example to support our main result.

we consider the concept of fuzzy quasi-contractions initiated by '{c}iri'{c} in the setting of fuzzy metric spaces and establish fixed point theorems for quasi-contractive mappings and for fuzzy $mathcal{h}$-contractive mappings on m-complete fuzzy metric spaces in the sense of george and veeramani.the results are illustrated by a representative example.