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Diff — Function (mathematics)

Revision #1242 → #2075 · back to history

modifiedGraph of a function152466608f49
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note`Function.graph f = {(a, b) | f a = b}` matches the graph definition, and `graph_injective` shows the representation is unique.`Function.graph f = {(a, b) | f a = b}` matches the graph definition.
modifiedImage of a function (range)dcfac4e461b5
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mathlib.moduleMathlib.Data.Set.ImageMathlib.Data.Set.Operations
addedSquare functione7da9953bdfd
addedCartesian product of two sets552171791a76
addedRiemann zeta function and Riemann hypothesis9ebba17313e9
modifiedUndecidability of recursive-function membership (Halting problem)21d5cc3509bd
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mathlib.declComputability.halting_problemComputablePred.halting_problem
note`halting_problem` proves `¬ComputablePred fun c => (eval c n).Dom`, the undecidability of the halting predicate.`ComputablePred.halting_problem` proves `¬ComputablePred fun c => (c.eval n).Dom`, the undecidability of the halting predicate.
modifiedMultiplication of integers as bivariate function98914ee1e68a
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mathlib.moduleMathlib.Data.Int.DefsInit.Data.Int.Basic
noteInteger multiplication is realized as a binary function via the `Mul ℤ` instance.Integer multiplication is realized as a binary function via `Int.mul` (and the `Mul ℤ` instance).
modifiedCartesian product of n setsbfd8c5ca88c1
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mathlib.moduleMathlib.Data.Set.ProdMathlib.Data.Set.Operations
addedNatural logarithm as bijection; exponential as inversef1951ab5895f
addedArccosine as inverse of restricted cosinec07edf68b16a
modifiedImplicit function theoremc725fd684d05
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note`HasStrictFDerivAt.implicitFunction` and its `prodFun_implicitFunction` equation provide the implicit function theorem in Banach spaces.`HasStrictFDerivAt.implicitFunction` provides the implicit function theorem in Banach spaces.
modifiedFunction defined as an antiderivative38fde9aadf2e
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mathlib.moduleMathlib.MeasureTheory.Integral.IntervalIntegralMathlib.MeasureTheory.Integral.IntervalIntegral.Basic
modifiedExponential function as solution of a differential equation1ff8034f78de
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mathlib.moduleMathlib.Analysis.SpecialFunctions.ExpMathlib.Analysis.Complex.Exponential
modifiedEmpty functiona33480fa3b47
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mathlib.moduleMathlib.Logic.IsEmpty.BasicMathlib.Logic.IsEmpty.Defs
modifiedCanonical surjection onto imagefb347c417b2a
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mathlib.moduleMathlib.Data.Set.ImageMathlib.Data.Set.Operations
modifiedIdentity functions are left/right identities7f525dcf955d
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mathlib.moduleMathlib.Logic.Function.DefsInit.Core
modifiedFiber of a point46e51dd712df
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noteThe fiber of `y` under `f` is `f ⁻¹' {y}`; `Function.fiber` in Mathlib.Logic.Function.FiberPartition packages this for partitioning.The fiber of `y` under `f` is `f ⁻¹' {y}`, a special case of `Set.preimage`.
modifiedBijective iff admits an inverse function44255e872fc5
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noteMathlib proves bijective is equivalent to having a two-sided inverse (`leftInverse_surjInv`/`rightInverse_surjInv`), and `Equiv.ofBijective` packages the inverse.`Function.bijective_iff_has_inverse` proves that bijective is equivalent to having a two-sided inverse.
modifiedCanonical factorization of a function930ea2a5483c
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mathlib.moduleMathlib.Data.Set.ImageMathlib.Data.Set.Operations
addedAnalytic continuationcf729b77b16c
modifiedPointwise operations on real functions1be3a1c2437f
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mathlib.moduleMathlib.Algebra.Group.Pi.BasicMathlib.Algebra.Notation.Pi.Defs
modifiedMonotonic real function485a3bd097e9
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mathlib.moduleMathlib.Order.DefsMathlib.Order.Monotone.Defs
addedSine and cosine as solutions of the linear ODE y'' = -y0cdd7397af3d
modifiedFunction spaceb5e4b569b431
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mathlib.moduleMathlib.Topology.ContinuousMap.BasicMathlib.Topology.ContinuousMap.Defs
modifiedEquivalence of models of computation; Church–Turing thesis1a6110c6ac64
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mathlib.declTuring.Partrec.to_TM2Turing.PartrecToTM2.tr_eval
noteMathlib formalizes equivalences between partial-recursive functions and Turing machine models in `Computability/TuringMachine/ToPartrec`, but a comprehensive Church-Turing equivalence covering all standard models is not packaged.`Turing.PartrecToTM2.tr_eval` formalizes that a TM2 machine simulates partial-recursive evaluation, but a comprehensive Church-Turing equivalence covering all standard models is not packaged.