Disjointness for measurably distal group actions and applications

We generalize Berg's notion of quasi-disjointness to actions of countable groups and prove that every measurably distal system is quasi-disjoint from every measure preserving system. As a corollary we obtain easy to check necessary and sufficient conditions for two systems to be disjoint, provided one of them is measurably distal. We also obtain a Wiener--Wintner type theorem for countable amenable groups with distal weights and applications to weighted multiple ergodic averages and multiple recurrence.Comment: 28 page

SOAR (Support Office for Aerogeophysical Research) Annual Report 1995/1996

The Support Office for Aerogeophysical Research (SOAR) was a facility of the National Science Foundation's Office of Polar Programs whose mission is to make airborne geophysical observations available to the broad research community of geology, glaciology and other sciences. The central office of the SOAR facility is located in Austin, Texas within the University of Texas Institute for Geophysics. Other institutions with significant responsibilities are the Lamont­ Doherty Earth Observatory of Columbia University and the Geophysics Branch of the U.S . Geological Survey. This report summarizes the goals and accomplishments of the SOAR facility during 1995/1996 and plans for the next year.National Science Foundation's Office of Polar ProgramsInstitute for Geophysic

A proof of a sumset conjecture of Erd\H{o}s

In this paper we show that every set $A \subset \mathbb{N}$ with positive density contains $B+C$ for some pair $B,C$ of infinite subsets of $\mathbb{N}$, settling a conjecture of Erd\H{o}s. The proof features two different decompositions of an arbitrary bounded sequence into a structured component and a pseudo-random component. Our methods are quite general, allowing us to prove a version of this conjecture for countable amenable groups.Comment: 54 pages. Corrected proof of Theorem 3.22 and added Example 3.27 Keywords: sum sets, almost periodic functions, ultrafilter

Problems on infinite sumset configurations in the integers and beyond

In contrast to finite arithmetic configurations, relatively little is known about which infinite patterns can be found in every set of natural numbers with positive density. Building on recent advances showing infinite sumsets can be found, we explore numerous open problems and obstructions to finding other infinite configurations in every set of natural numbers with positive density.Comment: 37 page

SOAR (Support Office for Aerogeophysical Research) Annual Report 1996/1997

The Support Office for Aerogeophysical Research (SOAR) was a facility of the National Science Foundation's Office of Polar Programs whose mission is to make airborne geophysical observations available to the broad research community of geology, glaciology and other sciences. The central office of the SOAR facility is located in Austin, Texas within the University of Texas Institute for Geophysics. Other institutions with significant responsibilities are the Lamont­ Doherty Earth Observatory of Columbia University and the Geophysics Branch of the U.S . Geological Survey. This report summarizes the goals and accomplishments of the SOAR facility during 1996/1997 and plans for the next year.National Science Foundation's Office of Polar ProgramsInstitute for Geophysic

Arctic sea-ice melt in 2008 and the role of solar heating

There has been a marked decline in the summer extent of Arctic sea ice over the past few decades. Data from autonomous ice mass-balance buoys can enhance our understanding of this decline. These buoys monitor changes in snow deposition and ablation, ice growth, and ice surface and bottom melt. Results from the summer of 2008 showed considerable large-scale spatial variability in the amount of surface and bottom melt. Small amounts of melting were observed north of Greenland, while melting in the southern Beaufort Sea was quite large. Comparison of net solar heat input to the ice and heat required for surface ablation showed only modest correlation. However, there was a strong correlation between solar heat input to the ocean and bottom melting. As the ice concentration in the Beaufort Sea region decreased, there was an increase in solar heat to the ocean and an increase in bottom melting

Ursinus College Bulletin, January 1985

A mandate to liberal arts colleges • Focus on faculty: The smart, curious and articulate • Liberal arts lauded on Founders Day • Campus plan: Preserving the classic college town • Cottage now counseling center • Hot time at homecoming • A one-man information explosion • Receptions set • Japan studies program offered • Books given • Photos shown • Faculty hired • Baton assigned • Evans and Hess appointed • Who\u27s whose confusing at legacy brunch • China trip for soccer team • Bruin notes • Grizzellany • Winter sports schedule • Class notes • For the love of legalities • He\u27ll make your weekend creepy • Marriages • Births • Deaths • Heefner new development chairman • Letters to the editorhttps://digitalcommons.ursinus.edu/new_bulletin/1041/thumbnail.jp

Ursinus College Alumni Journal, November 1967

75 years to Pluto • Welcome alumni! Oldtimers return to campus on Homecoming Day • Students cheer Loyalty Fund kick-off • Business & Pleasure • Honored on Founders\u27 Day • Habari safari: Ursinus men go to Africa • Contemporary drama • Development: Ursinus charts a course for the decade ahead • From the President • Birds of a feather gather together • Radio station WRUC entertains and informs the Collegeville community • Florida physician speaks in Yugoslavia • Walter Emerson Baum art show • Campus clippings: Graduate teacher training; Neighborhood dinner; Fall enrollment; End of an era; Parents day; New faculty members; Dutch visitor; Evening school • Sporting scene: Soccer; Hockey; Football; Cross country wins 11 straight • Class notebook • Weddings • Births • In memoriam • The business dollar in educationhttps://digitalcommons.ursinus.edu/alumnijournal/1090/thumbnail.jp