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  2. Envelope (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Envelope_(mathematics)

    Envelope (mathematics) Construction of the envelope of a family of curves. In geometry, an envelope of a planar family of curves is a curve that is tangent to each member of the family at some point, and these points of tangency together form the whole envelope. Classically, a point on the envelope can be thought of as the intersection of two ...

  3. Envelope theorem - Wikipedia

    en.wikipedia.org/wiki/Envelope_theorem

    Envelope theorem. In mathematics and economics, the envelope theorem is a major result about the differentiability properties of the value function of a parameterized optimization problem. [1] As we change parameters of the objective, the envelope theorem shows that, in a certain sense, changes in the optimizer of the objective do not ...

  4. Convex hull - Wikipedia

    en.wikipedia.org/wiki/Convex_hull

    The convex hull of the red set is the blue and red convex set. In geometry, the convex hull, convex envelope or convex closure[1] of a shape is the smallest convex set that contains it. The convex hull may be defined either as the intersection of all convex sets containing a given subset of a Euclidean space, or equivalently as the set of all ...

  5. Envelope (category theory) - Wikipedia

    en.wikipedia.org/wiki/Envelope_(category_theory)

    Envelope (category theory) In category theory and related fields of mathematics, an envelope is a construction that generalizes the operations of "exterior completion", like completion of a locally convex space, or Stone–Čech compactification of a topological space. A dual construction is called refinement.

  6. Back-of-the-envelope calculation - Wikipedia

    en.wikipedia.org/wiki/Back-of-the-envelope...

    Back-of-the-envelope calculation. A back-of-the-envelope calculation is a rough calculation, typically jotted down on any available scrap of paper such as an envelope. It is more than a guess but less than an accurate calculation or mathematical proof. The defining characteristic of back-of-the-envelope calculations is the use of simplified ...

  7. Envelope (waves) - Wikipedia

    en.wikipedia.org/wiki/Envelope_(waves)

    Envelope (waves) In physics and engineering, the envelope of an oscillating signal is a smooth curve outlining its extremes. [1] The envelope thus generalizes the concept of a constant amplitude into an instantaneous amplitude. The figure illustrates a modulated sine wave varying between an upper envelope and a lower envelope.

  8. Refinement (category theory) - Wikipedia

    en.wikipedia.org/wiki/Refinement_(category_theory)

    Refinement (category theory) In category theory and related fields of mathematics, a refinement is a construction that generalizes the operations of "interior enrichment", like bornologification or saturation of a locally convex space. A dual construction is called envelope.

  9. Moreau envelope - Wikipedia

    en.wikipedia.org/wiki/Moreau_envelope

    The Moreau envelope has important applications in mathematical optimization: minimizing over and minimizing over are equivalent problems in the sense that the sets of minimizers of and are the same. However, first-order optimization algorithms can be directly applied to , since may be non-differentiable while is always continuously differentiable.