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.
Sleep apnea is a breathing condition that's linked to being overweight. Sleep apnea can cause a person to snore heavily and to briefly stop breathing during sleep. Sleep apnea may cause daytime sleepiness and make heart disease and stroke more likely. Weight loss often improves sleep apnea.