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.
Thyroid Disease and Sleep Apnea. There is also a relationship between an increased incidence of sleep apnea (brief periods when you stop breathing while sleeping) and hypothyroidism. Frequent apnea can also cause unrelieved exhaustion. Apnea is often also seen in conjunction with snoring.