•
L'Hôpital's rule uses derivatives to find limits of indeterminate forms 0/0 or ±∞/∞, and only applies to such cases. •
Lamarck's theory of evolution has two laws: The first can be paraphrased as "use it or lose it". The second is the more famous law of
soft inheritance. •
Lambert's cosine law describes the radiant intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator. •
Lanchester's laws are formulae for calculating the relative strengths of predator/prey pair and application in military conflict. •
Landauer's principle: there is a minimum possible amount of energy required to change one bit of information, known as the Landauer limit. •
LaSalle's invariance principle is a criterion for the
asymptotic stability of an autonomous (possibly nonlinear) dynamical system. Named for mathematician
Joseph P. LaSalle. •
Leavitt's law: In astronomy, a period-luminosity relation linking the luminosity of pulsating variable stars with their pulsation period. Named for American astronomer
Henrietta Swan Leavitt. •
Lehman's laws of software evolution •
Leibniz's law is a principle in
metaphysics also known as the Identity of Indiscernibles. It states: "If two objects have all their properties in common, then they are one and the same object." •
Lenz's law: An induced current is always in such a direction as to oppose the motion or change causing it. Named for Russian physicist
Emil Lenz. •
Lem's law: "No one reads; if someone does read, he doesn't understand, if he understands, he immediately forgets." •
Lewis's law: "The comments on any article about feminism justify feminism." Named for English journalist
Helen Lewis. •
Lightwood's law: In medicine, states that bacterial infections will tend to localise while viral infections will tend to spread. •
Liebig's law of the minimum: The growth or distribution of a plant is dependent on the one environmental factor most critically in demand. •
Lindy's Law: the life expectancy of something is proportional to its current age. Something that has been around for a long time is likely to also remain around for a long time. •
Linus's law: "Given enough eyeballs, all
bugs are shallow." Named for
Linus Torvalds. •
Little's law, in
queuing theory: "The average number of customers in a stable system (over some time interval) is equal to their average arrival rate, multiplied by their average time in the system." The law was named for
John Little from results of experiments in 1961. •
Littlewood's law: individuals can expect miracles to happen to them, at the rate of about one per month. Coined by
J. E. Littlewood, (1885–1977). •
Liskov substitution principle in computer science is a particular definition of a subtyping relation, called (strong) behavioral subtyping. •
Llinás's law: "A neuron of a given kind cannot be functionally replaced by one of another type even if their synaptic connectivity and the type of neurotransmitter outputs are identical." Named for neuroscientist
Rodolfo Llinás. •
Lorentz force law defines the force on a moving charged particle in electric and magnetic fields. •
Lotka's law, in
infometrics: the number of authors publishing a certain number of articles is a fixed ratio to the number of authors publishing a single article. As the number of articles published increases, authors producing that many publications become less frequent. For example, there may be as many authors publishing two articles within a specified time period as there are single-publication authors, as many publishing three articles, as many publishing four articles, etc. Though the law itself covers many disciplines, the actual ratios involved are very discipline-specific. •
Lucas critique: "argues that it is naïve to try to predict the effects of a change in
economic policy entirely on the basis of relationships observed in historical data, especially highly
aggregated historical data." •
Madelung rule: the order in which atomic orbitals are filled according to the
aufbau principle. Named for
Erwin Madelung. Also known as the Janet rule or the Klechkowski rule (after
Charles Janet or
Vsevolod Klechkovsky). •
Maes–Garreau law: most favorable predictions about future technology will fall around latest possible date they can come true and still remain in the lifetime of the person making the prediction. •
Malthusian growth model, also referred to as the
Malthusian law or
simple exponential growth model, is
exponential growth based on a constant rate. The model is named after
Thomas Robert Malthus, who wrote
An Essay on the Principle of Population (1798), one of the earliest and most influential books on
population. •
Marconi's law empirically relates radio communication distance to antenna tower height. •
Maxwell's equations a set of coupled partial differential equations that, together with the
Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. •
Meadow's law is a precept, now discredited, that since cot deaths are so rare, "One is a tragedy, two is suspicious and three is
murder, until proved otherwise." It was named for
Roy Meadow, a discredited
paediatrician prominent in the United Kingdom in the last quarter of the twentieth century. •
Mendel's laws are named for the 19th century Austrian monk
Gregor Mendel who determined the patterns of inheritance through his plant breeding experiments, working especially with peas. Mendel's first law, or the law of segregation, states that each organism has a pair of
genes; that it inherits one from each parent, and that the organism will pass down only one of these genes to its own offspring. These different copies of the same gene are called
alleles. Mendel's second law, the law of independent assortment, states that different traits will be inherited independently by the offspring. •
Menzerath's law, or Menzerath–Altmann law (named after
Paul Menzerath and
Gabriel Altmann), is a linguistic law according to which the increase of a linguistic construct results in a decrease of its constituents, and vice versa. •
Metcalfe's law, in
communications and
network theory: the value of a system grows as approximately the square of the number of users of the system. Framed by
Robert Metcalfe in the context of
Ethernet. •
Miller's law, in communication: "To understand what another person is saying, you must assume that it is true and try to imagine what it could be true of." Named after
George Armitage Miller. •
Miller's rule, in optics, is an empirical rule which gives an estimate of the order of magnitude of the nonlinear coefficient. •
Monro–Kellie doctrine: The pressure–volume relationship between intracranial contents and
cerebral perfusion pressure (CPP) states that the cranial compartment is inelastic and that the volume inside the cranium is fixed. The cranium and its constituents (blood, CSF, and brain tissue) create a state of volume equilibrium, such that any increase in volume of one of the cranial constituents must be compensated by a decrease in volume of another.
*This concept only applies to adults, as the presence of fontanelles and open suture lines in infants that have not yet fused means there is potential for a change in size and intracranial volume. •
Morgan's canon "In no case is an animal activity to be interpreted in terms of higher psychological processes if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development." •
Mooers's law: "An information retrieval system will tend not to be used whenever it is more painful and troublesome for a customer to have information than for him not to have it." An empirical observation made by American
computer scientist Calvin Mooers in 1959. •
Moore's law is an empirical observation stating that the complexity of
integrated circuits doubles every 24 months. Outlined in 1965 by
Gordon Moore, co-founder of
Intel Corporation. •
Muller's ratchet where mutations in a species will tend to accumulate. •
Muphry's law: "If you write anything criticizing editing or proofreading, there will be a fault of some kind in what you have written." The name is a deliberate misspelling of "Murphy's law". •
Murphy's law: "Anything that can go wrong will go wrong." Ascribed to
Edward A. Murphy, Jr. See also
Sod's law. •
Murray's law states that, in physiological systems such as blood flow, no matter the diameter of the vessel, it will be structured such that minimal work is required to enable the maintenance of a steady state. Named after Cecil D. Murray. == N–Q ==