Documentation

Mathlib.Analysis.Complex.UnitDisc.Basic

PoincarΓ© disc #

In this file we define Complex.UnitDisc to be the unit disc in the complex plane. We also introduce some basic operations on this disc.

The complex unit disc, denoted as 𝔻 within the Complex namespace

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    The complex closed unit disc, denoted as 𝕔𝔻 within the Complex namespace

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      @[implicit_reducible]
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      The complex unit disc, denoted as 𝔻 within the Complex namespace

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        The complex closed unit disc, denoted as 𝕔𝔻 within the Complex namespace

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          Coercion to β„‚.

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            theorem Complex.UnitDisc.coe_injective_iff {a₁ aβ‚‚ : UnitDisc} :
            a₁ = aβ‚‚ ↔ ↑a₁ = ↑aβ‚‚
            @[simp]
            theorem Complex.UnitDisc.coe_inj {z w : UnitDisc} :
            ↑z = ↑w ↔ z = w
            @[simp]
            theorem Complex.UnitDisc.coe_mul (z w : UnitDisc) :
            ↑(z * w) = ↑z * ↑w
            @[simp]
            theorem Complex.UnitDisc.coe_neg (z : UnitDisc) :
            ↑(-z) = -↑z

            A constructor that assumes β€–zβ€– < 1 instead of dist z 0 < 1 and returns an element of 𝔻 instead of β†₯Metric.ball (0 : β„‚) 1.

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              def Complex.UnitDisc.casesOn {motive : UnitDisc β†’ Sort u_1} (mk : (z : β„‚) β†’ (hz : β€–zβ€– < 1) β†’ motive (mk z hz)) (z : UnitDisc) :
              motive z

              A cases eliminator that makes cases z use UnitDisc.mk instead of Subtype.mk.

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                @[simp]
                theorem Complex.UnitDisc.casesOn_mk {motive : UnitDisc β†’ Sort u_1} (mk' : (z : β„‚) β†’ (hz : β€–zβ€– < 1) β†’ motive (mk z hz)) {z : β„‚} (hz : β€–zβ€– < 1) :
                UnitDisc.casesOn mk' (mk z hz) = mk' z hz
                @[simp]
                theorem Complex.UnitDisc.coe_mk (z : β„‚) (hz : β€–zβ€– < 1) :
                ↑(mk z hz) = z
                @[simp]
                theorem Complex.UnitDisc.mk_coe (z : UnitDisc) (hz : ‖↑zβ€– < 1 := β‹―) :
                mk (↑z) hz = z
                @[simp]
                theorem Complex.UnitDisc.mk_inj {z w : β„‚} (hz : β€–zβ€– < 1) (hw : β€–wβ€– < 1) :
                mk z hz = mk w hw ↔ z = w
                theorem Complex.UnitDisc.forall {p : UnitDisc β†’ Prop} :
                (βˆ€ (z : UnitDisc), p z) ↔ βˆ€ (z : β„‚) (hz : β€–zβ€– < 1), p (mk z hz)
                theorem Complex.UnitDisc.exists {p : UnitDisc β†’ Prop} :
                (βˆƒ (z : UnitDisc), p z) ↔ βˆƒ (z : β„‚) (hz : β€–zβ€– < 1), p (mk z hz)
                @[simp]
                theorem Complex.UnitDisc.mk_neg (z : β„‚) (hz : β€–-zβ€– < 1) :
                mk (-z) hz = -mk z β‹―
                @[simp]
                theorem Complex.UnitDisc.coe_zero :
                ↑0 = 0
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                theorem Complex.UnitDisc.coe_eq_zero {z : UnitDisc} :
                ↑z = 0 ↔ z = 0
                @[simp]
                theorem Complex.UnitDisc.mk_eq_zero {z : β„‚} (hz : β€–zβ€– < 1) :
                mk z hz = 0 ↔ z = 0
                @[implicit_reducible]
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                @[simp]
                theorem Complex.UnitDisc.coe_circle_smul (z : Circle) (w : UnitDisc) :
                ↑(z β€’ w) = ↑z * ↑w
                @[deprecated Complex.UnitDisc.coe_circle_smul (since := "2026-01-06")]
                theorem Complex.UnitDisc.coe_smul_circle (z : Circle) (w : UnitDisc) :
                ↑(z β€’ w) = ↑z * ↑w

                Alias of Complex.UnitDisc.coe_circle_smul.

                @[implicit_reducible]
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                theorem Complex.UnitDisc.coe_pow (z : UnitDisc) (n : β„•+) :
                ↑(z ^ n) = ↑z ^ ↑n
                @[simp]
                theorem Complex.UnitDisc.pow_eq_zero {z : UnitDisc} {n : β„•+} :
                z ^ n = 0 ↔ z = 0

                Real part of a point of the unit disc.

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                  Imaginary part of a point of the unit disc.

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                    @[simp]
                    theorem Complex.UnitDisc.re_coe (z : UnitDisc) :
                    (↑z).re = z.re
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                    theorem Complex.UnitDisc.im_coe (z : UnitDisc) :
                    (↑z).im = z.im
                    @[simp]
                    @[simp]
                    @[simp]
                    @[simp]
                    @[implicit_reducible]

                    Conjugate point of the unit disc.

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                    @[deprecated Star.star (since := "2026-01-06")]

                    Conjugate point of the unit disc. Deprecated, use star instead.

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                      @[simp]
                      theorem Complex.UnitDisc.coe_star (z : UnitDisc) :
                      ↑(star z) = (starRingEnd β„‚) ↑z
                      @[deprecated Complex.UnitDisc.coe_star (since := "2026-01-06")]
                      theorem Complex.UnitDisc.coe_conj (z : UnitDisc) :
                      ↑(star z) = (starRingEnd β„‚) ↑z

                      Alias of Complex.UnitDisc.coe_star.

                      @[implicit_reducible]
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                      @[deprecated star_star (since := "2026-01-06")]
                      @[deprecated Complex.UnitDisc.star_neg (since := "2026-01-06")]

                      Alias of Complex.UnitDisc.star_neg.

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                      @[deprecated Complex.UnitDisc.re_star (since := "2026-01-06")]

                      Alias of Complex.UnitDisc.re_star.

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                      @[deprecated Complex.UnitDisc.im_star (since := "2026-01-06")]

                      Alias of Complex.UnitDisc.im_star.

                      @[deprecated star_mul' (since := "2026-01-06")]
                      theorem Complex.UnitDisc.conj_mul (z w : UnitDisc) :
                      star (z * w) = star z * star w
                      @[implicit_reducible]
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                      theorem Complex.UnitClosedDisc.coe_injective_iff {a₁ aβ‚‚ : UnitClosedDisc} :
                      a₁ = aβ‚‚ ↔ ↑a₁ = ↑aβ‚‚
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                      theorem Complex.UnitClosedDisc.coe_inj {z w : UnitClosedDisc} :
                      ↑z = ↑w ↔ z = w
                      @[simp]
                      theorem Complex.UnitClosedDisc.coe_mul (z w : UnitClosedDisc) :
                      ↑(z * w) = ↑z * ↑w
                      @[simp]
                      theorem Complex.UnitClosedDisc.coe_neg (z : UnitClosedDisc) :
                      ↑(-z) = -↑z

                      A constructor that assumes β€–zβ€– < 1 instead of dist z 0 < 1 and returns an element of 𝕔𝔻 instead of β†₯Metric.ball (0 : β„‚) 1.

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                        def Complex.UnitClosedDisc.casesOn {motive : UnitClosedDisc β†’ Sort u_1} (mk : (z : β„‚) β†’ (hz : β€–zβ€– ≀ 1) β†’ motive (mk z hz)) (z : UnitClosedDisc) :
                        motive z

                        A cases eliminator that makes cases z use UnitClosedDisc.mk instead of Subtype.mk.

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                          @[simp]
                          theorem Complex.UnitClosedDisc.casesOn_mk {motive : UnitClosedDisc β†’ Sort u_1} (mk' : (z : β„‚) β†’ (hz : β€–zβ€– ≀ 1) β†’ motive (mk z hz)) {z : β„‚} (hz : β€–zβ€– ≀ 1) :
                          UnitClosedDisc.casesOn mk' (mk z hz) = mk' z hz
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                          theorem Complex.UnitClosedDisc.coe_mk (z : β„‚) (hz : β€–zβ€– ≀ 1) :
                          ↑(mk z hz) = z
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                          theorem Complex.UnitClosedDisc.mk_coe (z : UnitClosedDisc) (hz : ‖↑zβ€– ≀ 1 := β‹―) :
                          mk (↑z) hz = z
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                          theorem Complex.UnitClosedDisc.mk_inj {z w : β„‚} (hz : β€–zβ€– ≀ 1) (hw : β€–wβ€– ≀ 1) :
                          mk z hz = mk w hw ↔ z = w
                          theorem Complex.UnitClosedDisc.forall {p : UnitClosedDisc β†’ Prop} :
                          (βˆ€ (z : UnitClosedDisc), p z) ↔ βˆ€ (z : β„‚) (hz : β€–zβ€– ≀ 1), p (mk z hz)
                          theorem Complex.UnitClosedDisc.exists {p : UnitClosedDisc β†’ Prop} :
                          (βˆƒ (z : UnitClosedDisc), p z) ↔ βˆƒ (z : β„‚) (hz : β€–zβ€– ≀ 1), p (mk z hz)
                          @[simp]
                          theorem Complex.UnitClosedDisc.mk_neg (z : β„‚) (hz : β€–-zβ€– ≀ 1) :
                          mk (-z) hz = -mk z β‹―
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                          @[simp]
                          theorem Complex.UnitClosedDisc.coe_closedBall_smul (z : UnitClosedDisc) (w : UnitDisc) :
                          ↑(z β€’ w) = ↑z * ↑w
                          @[deprecated Complex.UnitClosedDisc.coe_closedBall_smul (since := "2026-01-06")]
                          theorem Complex.UnitClosedDisc.coe_smul_closedBall (z : UnitClosedDisc) (w : UnitDisc) :
                          ↑(z β€’ w) = ↑z * ↑w

                          Alias of Complex.UnitClosedDisc.coe_closedBall_smul.

                          @[simp]
                          theorem Complex.UnitClosedDisc.coe_circle_smul (z : Circle) (w : UnitClosedDisc) :
                          ↑(z β€’ w) = ↑z * ↑w
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                          theorem Complex.UnitClosedDisc.coe_pow (z : UnitClosedDisc) (n : β„•) :
                          ↑(z ^ n) = ↑z ^ n

                          Real part of a point of the unit disc.

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                            Imaginary part of a point of the unit disc.

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                              @[simp]
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                              @[implicit_reducible]

                              Conjugate point of the unit disc.

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