Fractional idealIn mathematics, in particular commutative algebra, the concept of fractional ideal is introduced in the context of integral domains and is particularly fruitful in the study of Dedekind domains. In some sense, fractional ideals of an integral domain are like ideals where denominators are allowed. In contexts where fractional ideals and ordinary ring ideals are both under discussion, the latter are sometimes termed integral ideals for clarity. Let be an integral domain, and let be its field of fractions.
South KoreaSouth Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern part of the Korean Peninsula and borders North Korea along the Korean Demilitarized Zone. The country's western border is formed by the Yellow Sea, while its eastern border is defined by the Sea of Japan. South Korea claims to be the sole legitimate government of the entire peninsula and adjacent islands. It has a population of 51.96 million, of which roughly half live in the Seoul Capital Area, the fourth most populous metropolitan area in the world.
Geography of South KoreaSouth Korea is located in East Asia, on the southern portion of the Korean Peninsula located out from the far east of the Asian landmass. The only country with a land border to South Korea is North Korea, lying to the north with of the border running along the Korean Demilitarized Zone. South Korea is mostly surrounded by water and has of coast line along three seas; to the west is the Yellow Sea (called Sohae ; in South Korea, literally means west sea), to the south is the East China Sea, and to the east is the Sea of Japan (called Donghae ; in South Korea, literally means east sea).
Demographics of South KoreaDemographic features of the population of South Korea include population density, ethnicity, education level, health of the populace, economic status, religious affiliations, and other aspects of the population. In June 2012, South Korea's population reached 50 million, and by the end of 2016, South Korea's population peaked at about 51 million people. However, in recent years the total fertility rate (TFR) of South Korea has plummeted, leading some researchers to suggest that if current trends continue, the country's population will shrink to approximately 28 million people by the end of the 21st century.
El Niño–Southern OscillationEl Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there.
