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  2. Jordan's lemma - Wikipedia

    en.wikipedia.org/wiki/Jordan's_lemma

    The path C is the concatenation of the paths C 1 and C 2. Jordan's lemma yields a simple way to calculate the integral along the real axis of functions f(z) = e i a z g(z) holomorphic on the upper half-plane and continuous on the closed upper half-plane, except possibly at a finite number of non-real points z 1, z 2, …, z n.

  3. Extension by new constant and function names - Wikipedia

    en.wikipedia.org/wiki/Extension_by_new_constant...

    Shoenfield states the theorem in the form for a new function name, and constants are the same as functions of zero arguments. In formal systems that admit ordered tuples, extension by multiple constants as shown here can be accomplished by addition of a new constant tuple and the new constant names having the values of elements of the tuple.

  4. Poincaré lemma - Wikipedia

    en.wikipedia.org/wiki/Poincaré_lemma

    In mathematics, the Poincaré lemma gives a sufficient condition for a closed differential form to be exact (while an exact form is necessarily closed). Precisely, it states that every closed p-form on an open ball in R n is exact for p with 1 ≤ p ≤ n. [1] The lemma was introduced by Henri Poincaré in 1886. [2] [3]

  5. Summation by parts - Wikipedia

    en.wikipedia.org/wiki/Summation_by_parts

    The formula for an integration by parts is () ′ = [() ()] ′ (). Beside the boundary conditions , we notice that the first integral contains two multiplied functions, one which is integrated in the final integral ( g ′ {\displaystyle g'} becomes g {\displaystyle g} ) and one which is differentiated ( f {\displaystyle f} becomes f ...

  6. Racetrack principle - Wikipedia

    en.wikipedia.org/wiki/Racetrack_principle

    In calculus, the racetrack principle describes the movement and growth of two functions in terms of their derivatives.. This principle is derived from the fact that if a horse named Frank Fleetfeet always runs faster than a horse named Greg Gooseleg, then if Frank and Greg start a race from the same place and the same time, then Frank will win.

  7. Lifting-the-exponent lemma - Wikipedia

    en.wikipedia.org/wiki/Lifting-the-exponent_lemma

    The exact origins of the LTE lemma are unclear; the result, with its present name and form, has only come into focus within the last 10 to 20 years. [1] However, several key ideas used in its proof were known to Gauss and referenced in his Disquisitiones Arithmeticae. [2]

  8. Proof of Bertrand's postulate - Wikipedia

    en.wikipedia.org/wiki/Proof_of_Bertrand's_postulate

    In mathematics, Bertrand's postulate (now a theorem) states that, for each , there is a prime such that < <.First conjectured in 1845 by Joseph Bertrand, [1] it was first proven by Chebyshev, and a shorter but also advanced proof was given by Ramanujan.

  9. Gauss's lemma (number theory) - Wikipedia

    en.wikipedia.org/wiki/Gauss's_lemma_(number_theory)

    Generalizations of Gauss's lemma can be used to compute higher power residue symbols. In his second monograph on biquadratic reciprocity, [4]: §§69–71 Gauss used a fourth-power lemma to derive the formula for the biquadratic character of 1 + i in Z[i], the ring of Gaussian integers.