Harary’s & Randić’s ideas of “forcing” & “freedom” involve subsets of double bonds of Kekule structure such as to be unique to that Kekule structure. Such forcing sets are argued to be greatly generalizable to deal with various other coverings, and thence forcing seems to be fundamental, and of notable potential utility. Various forcing invariants associated to (molecular) graphs ensue, with il...

We (i.e. I) present a simplified version of Shelah’s “preserving a little implies preserving much”: If I is the ideal generated by a Suslin ccc forcing (e.g. Lebesque– null or meager), and P is a Suslin forcing, and P is I–preserving (i.e. it doesn’t make any positive Borel–set small), then P preserves generics over candidates and therefore is strongly I–preserving (i.e. doesn’t make any positi...

Abstract— In this article we show that a Code Division Multiple Access (CDMA) system employing long codes can be interpreted as a Multiple Input Multiple Output system where the transmit filters are time-varying. We derive conditions for existence of zero-forcing equalizers and verify through simulations that these conditions are useful guidelines for the design of appropriate solution in the p...

あらまし 厳しい周波数選択性環境下では大きな符号間干渉(ISI)が発生するため,シングルキャリア(SC)伝送の 平均ビット誤り率(BER)特性は著しく劣化してしまう.最近,周波数選択性フェージングを克服する技術として, 最小平均二乗誤差規範に基づく周波数領域等化(MMSE-FDE)が注目を浴びている.MMSE-FDE では,ISI を抑圧し つつ周波数ダイバーシチ利得を獲得できるため,SC 伝送の BER 特性を大幅に改善できる.しかし ISI が残留する ため,BER の理論的な下界を達成することはできない.筆者らはこれまで,送信機で Tomlinson-Harashima precoding (THP)を用いることで受信機での FDE 後の残留 ISI を抑圧し,特に 16QAM や 64QAM などの高レベル多値変調を用 いたときの BER 特性を改善できることを示してきた.本...

The effects of cooperating base stations in the downlink of an OFDM-based cellular network with frequency reuse factor one are studied. In this so-called network MIMO scenario the signals of several users are jointly processed before transmission in order to handle the unavoidable multi-user interference. We apply and study pre-processing techniques well-known from conventional MIMO scenarios i...

It is assumed that a Kripke-Joyal semantics A = 〈C,Cov,F, 〉 has been defined for a first-order language L. To transform C into a Heyting algebra C on which the forcing relation is preserved, a standard construction is used to obtain a complete Heyting algebra made up of cribles of C. A pretopology Cov is defined on C using the pretopology on C. A sheaf F is made up of sections of F that obey fu...

Spatial periodic forcing can entrain a pattern-forming system in the same way as temporal periodic forcing can entrain an oscillator. The forcing can lock the pattern's wave number to a fraction of the forcing wave number within tonguelike domains in the forcing parameter plane, it can increase the pattern's amplitude, and it can also create patterns below their onset. We derive these results u...

This survey paper examines the effective model theory obtained with the BSS model of real number computation. It treats the following topics: computable ordinals, satisfaction of computable infinitary formulas, forcing as a construction technique, effective categoricity, effective topology, and relations with other models for the effective theory of uncountable structures.

-This paper is concerned with the oscillation of solutions of higher order nonlinear delay difference equations with forcing terms of the form Anx(t) + f(t, x(t),x(a(t))) = h(t), t E I = {0, 1 . . . . }, where A is the forward difference operator defined by Ax(t) = x(t + 1) -x(t) and A'nx(t) = A(Am-lx(t)), m > 1. A necessary and sufficient condition is established under which every solution x(t...

The Proper Forcing Axiom is a powerful extension of the Baire Category Theorem which has proved highly effective in settling mathematical statements which are independent of ZFC. In contrast to the Continuum Hypothesis, it eliminates a large number of the pathological constructions which can be carried out using additional axioms of set theory. Mathematics Subject Classification (2000). Primary...