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 withinin the Complex namespace

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    The complex unit disc, denoted as 𝔻 withinin 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
            @[simp]
            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
            @[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.

            @[simp]
            theorem Complex.UnitDisc.coe_closedBall_smul (z : ↑(Metric.closedBall 0 1)) (w : UnitDisc) :
            ↑(z β€’ w) = ↑z * ↑w
            @[deprecated Complex.UnitDisc.coe_closedBall_smul (since := "2026-01-06")]
            theorem Complex.UnitDisc.coe_smul_closedBall (z : ↑(Metric.closedBall 0 1)) (w : UnitDisc) :
            ↑(z β€’ w) = ↑z * ↑w

            Alias of Complex.UnitDisc.coe_closedBall_smul.

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

                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.

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

                  Alias of Complex.UnitDisc.star_neg.

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

                  Alias of Complex.UnitDisc.re_star.

                  @[simp]
                  @[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