Mathematical Abstraction, Conceptual Variation and Identity

One of the key features of modern mathematics is the adoption of the abstract method. Our goal in this paper is to propose an explication of that method that is rooted in the history of the subject

Does the Swedish stock market exhibit mean reversion? : A study on the Stockholm Stock Exchange, its sectors and different market conditions

The purpose of this study is to examine whether the returns on the Stockholm Stock Exchange and its different sectors is mean reverting during the period 2003–2019. In addition to the examination of the entire period, the study also examines the periods before, during and after the global financial crisis. Daily, weekly and monthly data is used in combination with three different statistical methods in the form of ADF-tests, KPSS-tests and GPH-tests. The previous research conducted within the area yield different results but the tendency to find support for mean reversion increases during periods of economic uncertainty. The main standpoint used in previous literature and also this study is based on Famas (1970) publication about the efficient market hypothesis (EMH).  The results from the entire period are in line with the EMH where no robust indications for mean reversion is found neither for the specific sectors or the index itself. However, when the different periods are examined, in the period following the global financial crisis the healthcare and real estate sector show signs of mean reversion. In summary, the results show more support for mean reversion when the sectors are examined in relation to the entire Stockholm Stock Exchange. The conclusion based on these results is that an investor, in contrast to the EMH, can use the serial correlation in returns for these sectors as an indicator for when to buy and sell assets during periods as the one following the global financial crisis.

Fare-free public transport in Östergötland - a profitable measure?

I Östergötlands län fyller Östgötatrafiken en viktig samhällsroll som ansvariga för kollektivtrafiken. I länet sker över 30 miljoner resor årligen med Östgötatrafikens buss- och pendeltågstrafik. I Sverige och internationellt har det tidigare genomförts försök med nolltaxa i kollektivtrafiken, bland annat för att få fler att resa kollektivt, för att minska utsläpp och uppnå tidsbesparingar. Syftet med uppsatsen är att genomföra en samhällsekonomisk lönsamhetskalkyl för nolltaxa i kollektivtrafiken i Östergötland. Lönsamhetskalkyler bygger på välfärdsteori, där målet är att undersöka om ett projekt ökar välfärden för att slutligen användas som underlag till beslutsfattare. Arbetets lönsamhetskalkyl visar att nyttorna för samhället i första hand består av värdet av ökade resor och tidsbesparingar. Utsläpp från koldioxid och andra emissioner minskar även då fler börjar resa kollektivt. Kostnaderna i kalkylen utgörs främst av en ökad resursåtgång för att möta ett ökat resande. Totalt är nettonuvärdet negativt med cirka 0,5 miljoner kronor, vilket indikerar att projektet inte är lönsamt för samhället. Eventuellt är nettonuvärdet mer negativt beroende på om en omdiskuterad snedvridningseffekt även inkluderas i beräkningen. Vidare är nettonuvärdet avhängigt ett antagande om viss beläggningsgrad i busstrafiken under högtrafik, varför vidare undersökning kring den faktiska beläggningsgraden är av intresse.

Does the Swedish stock market exhibit mean reversion? : A study on the Stockholm Stock Exchange, its sectors and different market conditions

The purpose of this study is to examine whether the returns on the Stockholm Stock Exchange and its different sectors is mean reverting during the period 2003–2019. In addition to the examination of the entire period, the study also examines the periods before, during and after the global financial crisis. Daily, weekly and monthly data is used in combination with three different statistical methods in the form of ADF-tests, KPSS-tests and GPH-tests. The previous research conducted within the area yield different results but the tendency to find support for mean reversion increases during periods of economic uncertainty. The main standpoint used in previous literature and also this study is based on Famas (1970) publication about the efficient market hypothesis (EMH).  The results from the entire period are in line with the EMH where no robust indications for mean reversion is found neither for the specific sectors or the index itself. However, when the different periods are examined, in the period following the global financial crisis the healthcare and real estate sector show signs of mean reversion. In summary, the results show more support for mean reversion when the sectors are examined in relation to the entire Stockholm Stock Exchange. The conclusion based on these results is that an investor, in contrast to the EMH, can use the serial correlation in returns for these sectors as an indicator for when to buy and sell assets during periods as the one following the global financial crisis.