Monotonically Monolithic Spaces, Corson Compacts, and D-spaces

نویسنده

  • GARY GRUENHAGE
چکیده

Monotonically monolithic spaces were recently introduced by V.V. Tkachuk, and monotonically κ-monolithic spaces by O.Alas, Tkachuk, and R. Wilson. In this note we answer some of their questions by showing that monotonically ω-monolithic compact spaces must be Corson compact, yet there is a Corson compact space which is not monotonically ω-monolithic. We obtain a characterization of monotonic monolithity that shows its close relationship to condition (G) of P. Collins and R. Roscoe. We also give an easy proof of Tkachuk’s result that monotonically monolithic spaces are hereditarily Dspaces by applying a result involving nearly good relations, and finally, we generalize nearly good to nearly OK to similarly obtain L.-X. Peng’s result that weakly monotonically monolithic spaces are D-spaces.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A note on Volterra and Baire spaces

 In Proposition 2.6 in (G‎. ‎Gruenhage‎, ‎A‎. ‎Lutzer‎, ‎Baire and Volterra spaces‎, ‎textit{Proc‎. ‎Amer‎. ‎Math‎. ‎Soc.} {128} (2000)‎, ‎no‎. ‎10‎, ‎3115--3124) a condition that‎ ‎every point of $D$ is $G_delta$ in $X$ was overlooked‎. ‎So we‎ ‎proved some conditions by which a Baire space is equivalent to a‎ ‎Volterra space‎. ‎In this note we show that if $X$ is a‎ ‎monotonically normal $T_1...

متن کامل

Lindelöf property and the iterated continuous function spaces

We give an example of a compact space X whose iterated continuous function spaces Cp(X), CpCp(X), . . . are Lindelöf, but X is not a Corson compactum. This solves a problem of Gul’ko (Problem 1052 in [11]). We also provide a theorem concerning the Lindelöf property in the function spaces Cp(X) on compact scattered spaces with the ω1th derived set empty, improving some earlier results of Pol [12...

متن کامل

On function spaces of Corson-compact spaces

We apply elementary substructures to characterize the space Cp(X) for Corsoncompact spaces. As a result, we prove that a compact space X is Corson-compact, if Cp(X) can be represented as a continuous image of a closed subspace of (Lτ ) × Z, where Z is compact and Lτ denotes the canonical Lindelöf space of cardinality τ with one non-isolated point. This answers a question of Archangelskij [2].

متن کامل

Compact Monotonically Metacompact Spaces Are Metrizable

Monotonically metacompact spaces were recently introduced as an extension of the concept of monotonically compact spaces. In this note we answer a question of Popvassilev, and Bennett, Hart, and Lutzer, by showing that every compact, Hausdorff, monotonically (countably) metacompact space is metrizable. We also show that certain countable spaces fail to be monotonically (countably) metacompact.

متن کامل

Approximating Integrable Sets by Compacts Constructively

In locally compact spaces, (Borel-)measurable sets can be approximated by compact sets. Ulam extended this result to complete separable metric spaces. We give a constructive proof of Ulam’s theorem. It is first proved intuitionistically and then, using a logical ‘trick’ due to Ishihara, a proof acceptable in Bishop-style mathematics is obtained. We feel this proof provides some insight into Ish...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2010