We introduce the property “F-linked” of subsets of posets for a given free filter F on the natural numbers, and define the properties “μ-F-linked” and “θ-F-Knaster” for posets in a natural way. We show that θ-F-Knaster posets preserve strong types of unbounded families and of maximal almost disjoint families. Concerning iterations of such posets, we develop a general technique to construct θ-Fr-Knaster posets (where Fr is the Frechet ideal) via matrix iterations of <θ-ultrafilter-linked posets (restricted to some level of the (...) matrix). This is applied to prove consistency results about Cichoń's diagram (without using large cardinals) and to prove the consistency of the fact that, for each Yorioka ideal, the four cardinal invariants associated with it are pairwise different. At the end, we show that three strongly compact cardinals are enough to force that Cichoń's diagram can be separated into 10 different values. (shrink)

We investigate the set (ω) of partitions of the natural numbers ordered by ≤* where A ≤* B if by gluing finitely many blocks of A we can get a partition coarser than B. In particular, we determine the values of a number of cardinals which are naturally associated with the structure ((ω),≥*), in terms of classical cardinal invariants of the continuum.

We study the values of the higher dimensional cardinal characteristics for sets of functions $f:\omega ^\omega \to \omega ^\omega $ introduced by the second author in [8]. We prove that while the bounding numbers for these cardinals can be strictly less than the continuum, the dominating numbers cannot. We compute the bounding numbers for the higher dimensional relations in many well known models of $\neg \mathsf {CH}$ such as the Cohen, random and Sacks models and, as a byproduct show that, (...) with one exception, for the bounding numbers there are no $\mathsf {ZFC}$ relations between them beyond those in the higher dimensional Cichoń diagram. In the case of the dominating numbers we show that in fact they collapse in the sense that modding out by the ideal does not change their values. Moreover, they are closely related to the dominating numbers $\mathfrak {d}^\lambda _\kappa $. (shrink)

We explore the connection between combinatorial principles on uncountable cardinals, like stick and club, on the one hand, and the combinatorics of sets of reals and, in particular, cardinal invariants of the continuum, on the other hand. For example, we prove that additivity of measure implies that Martin’s axiom holds for any Cohen algebra. We construct a model in which club holds, yet the covering number of the null ideal is large. We show that for uncountable cardinals κ≤λ and , (...) if all subsets of λ either contain, or are disjoint from, a member of , then has size at least etc. As an application, we solve the Gross space problem under by showing that there is such a space over any countable field. In two appendices, we solve problems of Fuchino, Shelah and Soukup, and of Kraszewski, respectively. (shrink)

Let κ < λ be regular uncountable cardinals. Using a finite support iteration (in fact a matrix iteration) of ccc posets we obtain the consistency of b = a = κ < s = λ. If μ is a measurable cardinal and μ < κ < λ, then using similar techniques we obtain the consistency of b = κ < a = s = λ.

It is relatively consistent with ZFC that every countable $FU_{fin} $ space of weight N₁ is metrizable. This provides a partial answer to a question of G. Gruenhage and P. Szeptycki [GS1].

We show that Σ1 4-Amoeba-absoluteness implies that $\forall a \in \mathbb{R}(\omega^{L\lbrack a \rbrack}_1 < \omega^V_1)$ and, hence, Σ1 3-measurability. This answers a question of Haim Judah (private communication).

We show that g ≤ c(Sym(ω)) where g is the groupwise density number and c(Sym(ω)) is the cofinality of the infinite symmetric group. This solves (the second half of) a problem addressed by Thomas.

We prove that in many situations it is consistent with ZFC that part of the invariants involved in Cichon's diagram are equal to κ while the others are equal to λ, where $\kappa < \lambda$ are both arbitrary regular uncountable cardinals. We extend some of these results to the case when λ is singular. We also show that $\mathrm{cf}(\kappa_U(\mathscr{L})) < \kappa_A(\mathscr{M})$ is consistent with ZFC.

Brendle, J., H. Judah and S. Shelah, Combinatorial properties of Hechler forcing, Annals of Pure and Applied Logic 59 185–199. Using a notion of rank for Hechler forcing we show: assuming ωV1 = ωL1, there is no real in V[d] which is eventually different from the reals in L[ d], where d is Hechler over V; adding one Hechler real makes the invariants on the left-hand side of Cichoń's diagram equal ω1 and those on the right-hand side equal 2ω (...) and produces a maximal almost disjoint family of subsets of ω of size ω1; there is no perfect set of random reals over V in V[ r][ d], where r is random over V and d Hechler over V[r], thus answering a question of the first and second authors. (shrink)

We study some properties of the quotient forcing notions \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q_{tr(I)} = \wp(2^{< \omega})/tr(i)}$$\end{document} and PI = B(2ω)/I in two special cases: when I is the σ-ideal of meager sets or the σ-ideal of null sets on 2ω. We show that the remainder forcing RI = Qtr(I)/PI is σ-closed in these cases. We also study the cardinal invariant of the continuum \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathfrak{h}_{\mathbb{Q}}}$$\end{document}, the distributivity (...) number of the quotient \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Dense(\mathbb{Q})/nwd}$$\end{document}, in order to show that \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\wp(\mathbb{Q})/nwd}$$\end{document} collapses \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathfrak{c}}$$\end{document} to \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathfrak{h}_{\mathbb{Q}}}$$\end{document}, thus answering a question addressed in Balcar et al. (Fundamenta Mathematicae 183:59–80, 2004). (shrink)

Let A[ω]ω be a maximal almost disjoint family and assume P is a forcing notion. Say A is P-indestructible if A is still maximal in any P-generic extension. We investigate P-indestructibility for several classical forcing notions P. In particular, we provide a combinatorial characterization of P-indestructibility and, assuming a fragment of MA, we construct maximal almost disjoint families which are P-indestructible yet Q-destructible for several pairs of forcing notions . We close with a detailed investigation of iterated Sacks indestructibility.

We show the consistency of ${\frak o} <{\frak d}$ where ${\frak o}$ is the size of the smallest off-branch family, and ${\frak d}$ is as usual the dominating number. We also prove the consistency of ${\frak b} < {\frak a}$ with large continuum. Here, ${\frak b}$ is the unbounding number, and ${\frak a}$ is the almost disjointness number.

We investigate which filters onωcan contain towers, that is, a modulo finite descending sequence without any pseudointersection. We prove the following results:Many classical examples of nice tall filters contain no towers.It is consistent that tall analytic P-filters contain towers of arbitrary regular height.It is consistent that all towers generate nonmeager filters, in particular Borel filters do not contain towers.The statement “Every ultrafilter contains towers.” is independent of ZFC.Furthermore, we study many possible logical implications between the existence of towers in filters, (...) inequalities between cardinal invariants of filters $,${\rm{co}}{{\rm{f}}^{\rm{*}}}\left$,${\rm{no}}{{\rm{n}}^{\rm{*}}}\left$, and${\rm{co}}{{\rm{v}}^{\rm{*}}}\left$), and the existence of Luzin type families, that is, if${\cal F}$is a filter then${\cal X} \subseteq {[\omega ]^\omega }$is an${\cal F}$-Luzin family if$\left\{ {X \in {\cal X}:|X \setminus F| = \omega } \right\}$is countable for every$F \in {\cal F}$. (shrink)

We show that every dominating analytic set in the Baire space has a dominating closed subset. This improves a theorem of Spinas [15] saying that every dominating analytic set contains the branches of a uniform tree, i.e. a superperfect tree with the property that for every splitnode all the successor splitnodes have the same length. In [15], a subset of the Baire space is called u-regular if either it is not dominating or it contains the branches of a uniform tree, (...) and it was proved that Σ21-Kσ-regularity implies Σ21-u-regularity. Here we show that these properties are in fact equivalent. Since the proof of analytic u-regularity uses a game argument it was clear that determinacy implies u-regularity of all sets. Here we show that an inaccessible cardinal is enough to construct a model for projective u-regularity, namely it holds in Solovay's model. Finally we show that forcing with uniform trees is equivalent to Laver forcing. (shrink)

The Asian Logic Conference (ALC) is a major international event in mathematical logic. It features the latest scientific developments in the fields of mathematical logic and its applications, logic in computer science, and philosophical logic. The ALC series also aims to promote mathematical logic in the Asia-Pacific region and to bring logicians together both from within Asia and elsewhere for an exchange of information and ideas. This combined proceedings volume represents works presented or arising from the 14th and 15th ALCs.

We prove that in many situations it is consistent with ZFC that part of the invariants involved in Cichon's diagram are equal to $\kappa$ while the others are equal to $\lambda$, where $\kappa < \lambda$ are both arbitrary regular uncountable cardinals. We extend some of these results to the case when $\lambda$ is singular. We also show that $\mathrm{cf}) < \kappa_A$ is consistent with ZFC.

We investigate the effect of adding a single real on cardinal invariants associated with the continuum. We show:1. adding an eventually different or a localization real adjoins a Luzin set of size continuum and a mad family of size ω1;2. Laver and Mathias forcing collapse the dominating number to ω1, and thus two Laver or Mathias reals added iteratively always force CH;3. Miller's rational perfect set forcing preserves the axiom MA.

We show that it is consistent that Martin's axiom holds, the continuum is large, and yet the dual distributivity number ℌ is κ1. This answers a question of Halbeisen.

LetG be a group. CallG akC-group if every element ofG has less thank conjugates. Denote byP(G) the least cardinalk such that any subset ofG of sizek contains two elements which commute.It is shown that the existence of groupsG such thatP(G) is a singular cardinal is consistent withZFC. So is the existence of groupsG which are notkC but haveP(G) (...) questions, and improves results, of Faber, Laver and McKenzie. (shrink)

Say that a function π:n<ω→n (henceforth called a predictor) k-constantly predicts a real xnω if for almost all intervals I of length k, there is iI such that x(i)=π(x↾i). We study the k-constant prediction number vnconst(k), that is, the size of the least family of predictors needed to k-constantly predict all reals, for different values of n and k, and investigate their relationship.

We investigate the structure of ultrafilters on Boolean algebras in the framework of Tukey reducibility. In particular, this paper provides several techniques to construct ultrafilters which are not Tukey maximal. Furthermore, we connect this analysis with a cardinal invariant of Boolean algebras, the ultrafilter number, and prove consistency results concerning its possible values on Cohen and random algebras.

We construct a G δ set G ⊆ ω ω ×2 ω with null vertical sections such that each perfect set P ⊆2 ω meets almost all vertical sections of G in the following sense: we can define from P subsets S of ω of density zero such that whenever the section determined by x ∈ ω ω does not meet P , then x ∈ S for all but finitely many i . This generalizes theorems of Mokobodzki and (...) class='Hi'>Brendle et al. 185–199). (shrink)

If $\mathcal{F}$ is a filter on $\omega$, we say that $\mathcal{F}$ is Canjar if the corresponding Mathias forcing does not add a dominating real. We prove that any Borel Canjar filter is $F_{\sigma}$, solving a problem of Hrušák and Minami. We give several examples of Canjar and non-Canjar filters; in particular, we construct a $\mathsf{MAD}$ family such that the corresponding Mathias forcing adds a dominating real. This answers a question of Brendle. Then we prove that in all the “classical” (...) models of $\mathsf{ZFC}$ there are $\mathsf{MAD}$ families whose Mathias forcing does not add a dominating real. We also study ideals generated by branches, and we uncover a close relation between Canjar ideals and the selection principle $S_{\mathrm{fin}}$ on subsets of the Cantor space. (shrink)

We give an affirmative answer to Brendle's and Hrušák's question of whether the club principle together with h > N₁ is consistent. We work with a class of axiom A forcings with countable conditions such that q ≥ n p is determined by finitely many elements in the conditions p and q and that all strengthenings of a condition are subsets, and replace many names by actual sets. There are two types of technique: one for tree-like forcings and one (...) for forcings with creatures that are translated into trees. Both lead to new models of the club principle. (shrink)

We show that it is independent whether club $\kappa $ -Miller forcing preserves $\kappa ^{++}$. We show that under $\kappa ^{ \kappa $, club $\kappa $ -Miller forcing collapses $\kappa ^{<\kappa }$ to $\kappa $. Answering a question by Brendle, Brooke-Taylor, Friedman and Montoya, we show that the iteration of ultrafilter $\kappa $ -Miller forcing does not have the Laver property.

Для широкого круга читателей (слушателей, аспирантов, преподавателей) интересующихся данной проблемой.

We show that after forcing with a countable support iteration or a finite product of Sacks or splitting forcing over L, every analytic hypergraph on a Polish space admits a $\mathbf {\Delta }^1_2$ maximal independent set. This extends an earlier result by Schrittesser (see [25]). As a main application we get the consistency of $\mathfrak {r} = \mathfrak {u} = \mathfrak {i} = \omega _2$ together with the existence of a $\Delta ^1_2$ ultrafilter, a $\Pi ^1_1$ maximal independent family, and (...) a $\Delta ^1_2$ Hamel basis. This solves open problems of Brendle, Fischer, and Khomskii [5] and the author [23]. We also show in ZFC that $\mathfrak {d} \leq \mathfrak {i}_{cl}$, addressing another question from [5]. (shrink)

We give results exploring the relationship between dominating and unbounded reals in Hechler extensions, as well as the relationships among the extensions themselves. We show that in the standard Hechler extension there is an unbounded real which is dominated by every dominating real, but that this fails to hold in the tree Hechler extension. We prove a representation theorem for dominating reals in the standard Hechler extension: every dominating real eventually dominates a sandwich composition of the Hechler real with two (...) ground model reals that monotonically converge to infinity. We apply our results to negatively settle a conjecture of Brendle and Löwe (Conjecture 15 of [4]). We also answer a question due to Laflamme. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:570 BOOK REVIEWS like reasonable rule for economic life. This effort is worthy of more attention than is possible here, but let it be noted that it must inevitably suffer the same fate as any ethical calculus: someone must decide for others what is their due and what is not. How much wealth, for example, makes for a concentration [of wealth] that would be " demonstrably detrimental to some (...) people's exercise of their generic rights "? His is ultimately an entitlement or rights ethic, rather than an aitial ethic of goal-purposive fulfillment for the individual, projected outwards for a common good scenario. While his rejection of goal ethics's inability to detail principles for distribution of goods is noteworthy, it does not appear that a tightened version of generic rights theory will come closer to either of Phillips's desiderata: a justification of moral reasoning apart from any theory of nature or a calculus for its application. Desan and Phillips wish to think against the limits of the human situation. For Desan, rising above limitation is a moral task and obligation facing us each, if there is to be a common future. His call is to be World Citizen in a Polis of Nations. Phillips's vision is more concrete, a distribution of benefits to benefit all with well-being and freedom. But this mundane task is no less difficult than Desan's transcendent one. Indeed, according to Augustine, even the Divine Mind must utilize an artifice in dealing with human creation: "He loves each of us as though there were only one of us." Both ethicists have striven to show us how we might think this vision for ourselves, i.e., for each other of us. ]OIIN B. DAVIS, O.P. ' Detroit, Michigan Catholics, Anglicans, and Puritans: Seventeenth-Century Essays. By HUGH TREVOR-ROPER. Chicago: The University of Chicago Press, 1988. Pp. xiii + 317. $27.50 (hardbound). Even to list the changes and events which occurred in seventeenth century England is a difficult task: the century spans the period from the death of Queen Elizabeth to the Glorious Revolution and beyond, through the Civil War, the accession and exile (twice) of the Stuarts, the rise of science, the transformation of the theological and religious issues of the English Reformation, to name only the most obvious. To conceive a book, in the form of occasional essays, which not only addresses these changes and events but does so by establishing the connections which were present with European currents at the same time surely tempts fate, even when it does not tempt reviewers. BOOK REVIEWS 571 But Hugh Trevor-Roper is a master, both of the period under survey and of the form of the essay. With one exception, each of these essays began as a lecture or seminar paper, and the pleasantly legible style in which they are written must bear some trace of that origin. The occasional flashes of wit, mixed with rthe fairly non-technical style, make the book a joy to read and a welcome escape from the usually constipated style of scholarly prose. In his Introduction, the essayist clearly sets forth his thesis that English intellectual history does not exist apart from the currents of European intellectual history (a thesis for which Trevor-Roper has already staked a claim). That leads to what may very well be the major problem with these essays: its end is in its beginning. The list of names cited in these essays only partially coincides with the list of names in the index; the former is much longer than the latter. And while the style of the essay welcomes the reader to the period, it also throws up more names and places and events than can be explained or even annotated adequately. This occurs both on a large and on a small scale. The first essay, on "Nicholas Hill, the English Atomist" contains such a vast array of names that at times it becomes the prosopo· graphical equivalent of a telephone book. On a large scale, there is the problem with a definition of Arminianism. No definition, at least no formal definition, is attempted-and this is probably wise. But, particularly in... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:BOOK REVIEWS The Inference That Makes Science. By ERNAN McMULLIN. The Aquinas Lecture, 1992. Milwaukee: Marquette University Press, 1992. Pp. iv +112. In this ambitious lecture Father Ernan McMullin recapitulates and refines a thesis that has guided his thought for the past forty years. In essence the thesis is this: precisely how science is made has eluded the best minds for centuries, and only in the work of Charles (...) Sanders Peirce, suitably emended by McMullin, has the puzzle finally been solved. " Retroduction " is the inference that makes science. Once this is understood, errors on what constitutes scientific method-those of Aristotle, Aquinas, Galileo, Newton, Bacon, Hume, et al.-can be rectified and one can see science for what it truly is: a complex process of theory appraisal that yields, not definitive truth, but well-established results to which assent can be given with at best "practical certainty," whatever that might be (pp. 91-96). Why McMullin should have chosen such a theme for an Aquinas Lecture is a question that defies reasonable answer. Surely one does not have to he so negative about the thought of Aristotle, Aquinas, and Galileo to advance one's ideas about science in the present day. What McMullin could easily have done, and he hints at this in the last two paragraphs of his lecture (pp. 97-98), is show how retroduction is itself simply a relaxed version of the demonstrative regress, the method actually endorsed by Aristotle, Aquinas, and Galileo. Such a retroductive version, fair enough, yields knowledge of a probable cause, the type of knowledge most typical of modern science. McMullin did not have to embark on the dangerous course of trying to prove that proof and certainty are forever beyond the grasp of science, or that never in the history of science has anyone established a definitive truth. That, in effect, is what McMullin has tried to do, and in the attempt to make the point he fumbles at almost every juncture throughout a very long lecture. To set the record straight more than a review is being re--·quested; perhaps a book, and even that might not suffice for those whose minds are made up. To understand the import of the lecture one must appreciate that it is hut a brief episode in a debate over demonstration in science that has been going on since McMullin first came to the University of Notre Dame in 1954. I myself have published many hooks and articles that engage the very point of his lecture and provide the contra evidence to 131 132 BOOK REVIEWS show elements of continuity in scientific method from Aristotle to the present. My last two volumes, in press at the same time as McMullin's Aquinas Lecture, answer in detail the aporiai he there raises.1 I need 1 Galileo's Logic of Discovery and Proof. The Backgrnund, Content, and Use of His Appropriated Treatises on Aristotle's Posterior Analytics. Boston Studies in the Philosophy of Science 137. Dordrecht-Boston-London: Kluwer Academic Publishers, 1992, xxiii + 323 pp.; Galileo's Logical Treatises. A Translation, with Notes and Commentary, of His Appropriated Questions on Aristotle's Posterior Analytics. Boston Studies in the Philosophy of Science 138. DordrechtBoston -London: Kluwer Academic Publishers, 1992, xix + 239 pp. only refer the interested reader to them for an extended and documented reply to his arguments. Some idea of the flavor of our debate, however, can be gained from the following. To support his thesis, McMullin has to maintain that Aristotle's proof that the moon is a sphere (from its having phases) and that Galileo's proofs that there are mountains on the moon, that Jupiter has satellites, and that Venus circles the sun (all based on telescopic observations) are not strictly demonstrative, that is, they do not yield true and certain conclusions. He declines to answer a query I have often tendered whether he personally is certain on the basis of pre-spacecraft evidence that the moon is a sphere, that there are mountains on it, that Jupiter has satellites, and so on. Instead he offers the categorical response "that planetary science is not an apodictic science, indeed that no natural science is... (shrink)

In this survey paper we collect several known results on destroying tall ideals on countable sets and maximal almost disjoint families with forcing. In most cases we provide streamlined proofs of the presented results. The paper contains results of many authors as well as a preview of results of a forthcoming paper of Brendle, Guzmán, Hrušák, and Raghavan.

According to [M.S. Kurilić, Cohen-stable families of subsets of the integers, J. Symbolic Logic 66 257–270], adding a Cohen real destroys a splitting family on ω if and only if is isomorphic to a splitting family on the set of rationals, , whose elements have nowhere dense boundaries. Consequently, implies the Cohen-indestructibility of . Using the methods developed in [J. Brendle, S. Yatabe, Forcing indestructibility of MAD families, Ann. Pure Appl. Logic 132 271–312] the stability of splitting families in (...) several forcing extensions is characterized in a similar way . Also, it is proved that a splitting family is preserved by the Sacks forcing if and only if it is preserved by some forcing which adds a new real. The corresponding hierarchy of splitting families is investigated. (shrink)