Discrete Mathematics/Functions and relations. This article examines the concepts of the function and the relation. A relation is any association or link between elements of one set, called the domain or (less formally) the set of inputs, and another set, called the range or set of outputs.
Sleep deprivation. Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function.
1 Sleeplessness may cause brain shrinkage. 2  A 2010 study linked chronic insomniacs to the loss in brain density, and researchers found, as Discovery News wrote, brain imaging has linked chronic insomnia to lower gray matter density in areas that regulate the brain's ability to make decisions and to rest..