Definition. Let X be a metric space with metric d. (a) A collection {G α } α∈A of open sets is called an open cover of X if every x ∈ X belongs to at least one of the G α , α ∈ A. An open cover is finite if the index set A is finite. (b) X is compact if every open cover of X contains a finite subcover. Definition. Let X be a metric space with metric d and let A ⊂ X. We say that A is a compact s...

We know that there is an isomorphism between the moduli space of gauge equivalence classes of flat G-connections on a compact surface and the moduli space of representations from the fundamental group of the surface to G acted on by the adjoint action (cf: Goldman[G]). It is known that if G is compact, semi-simple and simply connected, the moduli space of gauge equivalence classes of flat G-con...

Let X be a non-locally convex F-space (complete metric linear space) whose dual X' separates the points of X. Then it is known that X possesses a closed subspace N which fails to be weakly closed (see [3]), or, equivalently, such that the quotient space XIN does not have a point separating dual. However the question has also been raised by Duren, Romberg and Shields [2] of whether X possesses a...

Let P be the natural forcing for producing a finite splitting tree using finite conditions. Namely, p ∈ P iff p ⊆ ω is a finite subtree and p ≤ q iff p ⊇ q is an end extension of q. End extension means if s ∈ p\q then s ⊇ t for some t ∈ q which is terminal in q, i.e., has no extensions in q. This order is countable and hence forcing equivalent to adding a single Cohen real. The union of P-gener...

during a very long period of time, civil engineers have been the only ones to be designated as the experts for underground space, while the planners and architects were the ones of the development at the surface. cities worldwide tend to overlook an invaluable asset that lies beneath their surfaces. most cities and urban regions are unaware of the benefits underground space use has to offer, bo...