diff --git a/common/src/math/domain.mjs b/common/src/math/domain.mjs
index 48bf8ad..19586ee 100644
--- a/common/src/math/domain.mjs
+++ b/common/src/math/domain.mjs
@@ -24,6 +24,7 @@ import { Expression, executeExpression } from "./expression.mjs"
  */
 export class Domain {
     constructor() {
+        this.latexMarkup = "#INVALID"
     }
 
     /**
@@ -206,8 +207,8 @@ export class Range extends Domain {
     }
 
     includes(x) {
-        if(x instanceof Expression) x = x.execute()
         if(typeof x == "string") x = executeExpression(x)
+        if(x instanceof Expression) x = x.execute()
         return ((this.openBegin && x > this.begin.execute()) || (!this.openBegin && x >= this.begin.execute())) &&
             ((this.openEnd && x < this.end.execute()) || (!this.openEnd && x <= this.end.execute()))
     }
@@ -249,15 +250,17 @@ export class SpecialDomain extends Domain {
     /**
      * @constructs SpecialDomain
      * @param {string} displayName
+     * @param {string} latexMarkup - markup representing the domain.
      * @param {function} isValid - function returning true when number is in domain false when it isn't.
      * @param {function} next - function provides the next positive value in the domain after the one given.
      * @param {function} previous - function provides the previous positive value in the domain before the one given.
      * @param {boolean} moveSupported - Only true if next and previous functions are valid.
      */
-    constructor(displayName, isValid, next = () => true, previous = () => true,
+    constructor(displayName, latexMarkup, isValid, next = () => true, previous = () => true,
         moveSupported = true) {
         super()
         this.displayName = displayName
+        this.latexMarkup = latexMarkup
         this.isValid = isValid
         this.nextValue = next
         this.prevValue = previous
@@ -562,39 +565,54 @@ Domain.RPE.latexMarkup = "\\mathbb{R}^{+*}"
 Domain.RME = new Range(-Infinity, 0, true, true)
 Domain.RME.displayName = "ℝ⁻*"
 Domain.RME.latexMarkup = "\\mathbb{R}^{+*}"
-Domain.N = new SpecialDomain("ℕ", x => x % 1 === 0 && x >= 0,
+Domain.N = new SpecialDomain(
+    "ℕ", "\\mathbb{N}",
+    x => x % 1 === 0 && x >= 0,
     x => Math.max(Math.floor(x) + 1, 0),
-    x => Math.max(Math.ceil(x) - 1, 0))
-Domain.N.latexMarkup = "\\mathbb{N}"
-Domain.NE = new SpecialDomain("ℕ*", x => x % 1 === 0 && x > 0,
+    x => Math.max(Math.ceil(x) - 1, 0)
+)
+Domain.NE = new SpecialDomain(
+    "ℕ*", "\\mathbb{N}^{*}",
+    x => x % 1 === 0 && x > 0,
     x => Math.max(Math.floor(x) + 1, 1),
-    x => Math.max(Math.ceil(x) - 1, 1))
-Domain.NE.latexMarkup = "\\mathbb{N}^{*}"
-Domain.Z = new SpecialDomain("ℤ", x => x % 1 === 0, x => Math.floor(x) + 1, x => Math.ceil(x) - 1)
-Domain.Z.latexMarkup = "\\mathbb{Z}"
-Domain.ZE = new SpecialDomain("ℤ*", x => x % 1 === 0 && x !== 0,
+    x => Math.max(Math.ceil(x) - 1, 1)
+)
+Domain.Z = new SpecialDomain(
+    "ℤ", "\\mathbb{Z}",
+    x => x % 1 === 0,
+    x => Math.floor(x) + 1,
+    x => Math.ceil(x) - 1
+)
+Domain.ZE = new SpecialDomain(
+    "ℤ*", "\\mathbb{Z}^{*}",
+    x => x % 1 === 0 && x !== 0,
     x => Math.floor(x) + 1 === 0 ? Math.floor(x) + 2 : Math.floor(x) + 1,
-    x => Math.ceil(x) - 1 === 0 ? Math.ceil(x) - 2 : Math.ceil(x) - 1)
-Domain.ZE.latexMarkup = "\\mathbb{Z}^{*}"
-Domain.ZM = new SpecialDomain("ℤ⁻", x => x % 1 === 0 && x <= 0,
+    x => Math.ceil(x) - 1 === 0 ? Math.ceil(x) - 2 : Math.ceil(x) - 1
+)
+Domain.ZM = new SpecialDomain(
+    "ℤ⁻", "\\mathbb{Z}^{-}",
+    x => x % 1 === 0 && x <= 0,
     x => Math.min(Math.floor(x) + 1, 0),
-    x => Math.min(Math.ceil(x) - 1, 0))
-Domain.ZM.latexMarkup = "\\mathbb{Z}^{-}"
-Domain.ZME = new SpecialDomain("ℤ⁻*", x => x % 1 === 0 && x < 0,
+    x => Math.min(Math.ceil(x) - 1, 0)
+)
+Domain.ZME = new SpecialDomain(
+    "ℤ⁻*", "\\mathbb{Z}^{-*}",
+    x => x % 1 === 0 && x < 0,
     x => Math.min(Math.floor(x) + 1, -1),
-    x => Math.min(Math.ceil(x) - 1, -1))
-Domain.ZME.latexMarkup = "\\mathbb{Z}^{-*}"
-Domain.NLog = new SpecialDomain("ℕˡᵒᵍ",
+    x => Math.min(Math.ceil(x) - 1, -1)
+)
+Domain.NLog = new SpecialDomain(
+    "ℕˡᵒᵍ", "\\mathbb{N}^{log}",
     x => x / Math.pow(10, Math.ceil(Math.log10(x))) % 1 === 0 && x > 0,
-    function(x) {
+    x => {
         let x10pow = Math.pow(10, Math.ceil(Math.log10(x)))
         return Math.max(1, (Math.floor(x / x10pow) + 1) * x10pow)
     },
-    function(x) {
+    x => {
         let x10pow = Math.pow(10, Math.ceil(Math.log10(x)))
         return Math.max(1, (Math.ceil(x / x10pow) - 1) * x10pow)
-    })
-Domain.NLog.latexMarkup = "\\mathbb{N}^{log}"
+    }
+)
 
 let refedDomains = []
 
@@ -626,7 +644,7 @@ export function parseDomainSimple(domain) {
     if(domain.includes("U") || domain.includes("∪")) return UnionDomain.import(domain)
     if(domain.includes("∩")) return IntersectionDomain.import(domain)
     if(domain.includes("∖") || domain.includes("\\")) return MinusDomain.import(domain)
-    if(domain.charAt(0) === "{" && domain.charAt(domain.length - 1) === "}") return DomainSet.import(domain)
+    if(domain.at(0) === "{" && domain.at(-1) === "}") return DomainSet.import(domain)
     if(domain.includes("]") || domain.includes("[")) return Range.import(domain)
     if(["R", "ℝ", "N", "ℕ", "Z", "ℤ"].some(str => domain.toUpperCase().includes(str)))
         return Domain.import(domain)
diff --git a/common/test/math/domain.mjs b/common/test/math/domain.mjs
index e32dbd1..6c2b93e 100644
--- a/common/test/math/domain.mjs
+++ b/common/test/math/domain.mjs
@@ -19,46 +19,90 @@
 import { describe, it } from "mocha"
 import { expect } from "chai"
 
-// import { Domain, parseDomainSimple } from "../../src/math/domain.mjs"
-//
-// describe("math.domain", function() {
-//     describe("#parseDomainSimple", function() {
-//         it("returns predefined domains", function() {
-//             const predefinedToCheck = [
-//                 // Real domains
-//                 { domain: Domain.R, shortcuts: ["R", "ℝ"] },
-//                 // Zero exclusive real domains
-//                 { domain: Domain.RE, shortcuts: ["RE", "R*", "ℝ*"] },
-//                 // Real positive domains
-//                 { domain: Domain.RP, shortcuts: ["RP", "R+", "ℝ⁺", "ℝ+"] },
-//                 // Zero-exclusive real positive domains
-//                 { domain: Domain.RPE, shortcuts: ["RPE", "REP", "R+*", "R*+", "ℝ*⁺", "ℝ⁺*", "ℝ*+", "ℝ+*"] },
-//                 // Real negative domain
-//                 { domain: Domain.RM, shortcuts: ["RM", "R-", "ℝ⁻", "ℝ-"] },
-//                 // Zero-exclusive real negative domains
-//                 { domain: Domain.RME, shortcuts: ["RME", "REM", "R-*", "R*-", "ℝ⁻*", "ℝ*⁻", "ℝ-*", "ℝ*-"] },
-//                 // Natural integers domain
-//                 { domain: Domain.N, shortcuts: ["ℕ", "N", "ZP", "Z+", "ℤ⁺", "ℤ+"] },
-//                 // Zero-exclusive natural integers domain
-//                 { domain: Domain.NE, shortcuts: ["NE", "NP", "N*", "N+", "ℕ*", "ℕ⁺", "ℕ+", "ZPE", "ZEP", "Z+*", "Z*+", "ℤ⁺*", "ℤ*⁺", "ℤ+*", "ℤ*+"] },
-//                 // Logarithmic natural domains
-//                 { domain: Domain.NLog, shortcuts: ["NLOG", "ℕˡᵒᵍ", "ℕLOG"] },
-//                 // All integers domains
-//                 { domain: Domain.Z, shortcuts: ["Z", "ℤ"] },
-//                 // Zero-exclusive all integers domain
-//                 { domain: Domain.ZE, shortcuts: ["ZE", "Z*", "ℤ*"] },
-//                 // Negative integers domain
-//                 { domain: Domain.ZM, shortcuts: ["ZM", "Z-", "ℤ⁻", "ℤ-"] },
-//                 // Zero-exclusive negative integers domain
-//                 { domain: Domain.ZME, shortcuts: ["ZME", "ZEM", "Z-*", "Z*-", "ℤ⁻*", "ℤ*⁻", "ℤ-*", "ℤ*-"] },
-//             ]
-//
-//             // Real domains
-//             for(const { domain, shortcuts } of predefinedToCheck)
-//                 for(const shortcut of shortcuts)
-//                     expect(parseDomainSimple(shortcut)).to.be.equal(domain)
-//         })
-//
-//         it("")
-//     })
-// })
+import { Domain, EmptySet, parseDomainSimple } from "../../src/math/domain.mjs"
+
+describe("math.domain", function() {
+    describe("#parseDomainSimple", function() {
+        it("returns empty sets when a domain cannot be parsed", function() {
+            expect(parseDomainSimple("∅")).to.be.an.instanceof(EmptySet)
+            expect(parseDomainSimple("O")).to.be.an.instanceof(EmptySet)
+            expect(parseDomainSimple("AAAAAAAAA")).to.be.an.instanceof(EmptySet)
+            expect(parseDomainSimple("???")).to.be.an.instanceof(EmptySet)
+            expect(parseDomainSimple("∅").latexMarkup).to.equal("\\emptyset")
+            expect(parseDomainSimple("???").toString()).to.equal("∅")
+            expect(parseDomainSimple("∅").includes(0)).to.be.false
+            expect(parseDomainSimple("∅").includes(Infinity)).to.be.false
+            expect(parseDomainSimple("∅").includes(-3)).to.be.false
+
+        })
+
+        it("returns predefined domains", function() {
+            const predefinedToCheck = [
+                // Real domains
+                { domain: Domain.R, shortcuts: ["R", "ℝ"] },
+                // Zero exclusive real domains
+                { domain: Domain.RE, shortcuts: ["RE", "R*", "ℝ*"] },
+                // Real positive domains
+                { domain: Domain.RP, shortcuts: ["RP", "R+", "ℝ⁺", "ℝ+"] },
+                // Zero-exclusive real positive domains
+                { domain: Domain.RPE, shortcuts: ["RPE", "REP", "R+*", "R*+", "ℝ*⁺", "ℝ⁺*", "ℝ*+", "ℝ+*"] },
+                // Real negative domain
+                { domain: Domain.RM, shortcuts: ["RM", "R-", "ℝ⁻", "ℝ-"] },
+                // Zero-exclusive real negative domains
+                { domain: Domain.RME, shortcuts: ["RME", "REM", "R-*", "R*-", "ℝ⁻*", "ℝ*⁻", "ℝ-*", "ℝ*-"] },
+                // Natural integers domain
+                { domain: Domain.N, shortcuts: ["ℕ", "N", "ZP", "Z+", "ℤ⁺", "ℤ+"] },
+                // Zero-exclusive natural integers domain
+                { domain: Domain.NE, shortcuts: ["NE", "NP", "N*", "N+", "ℕ*", "ℕ⁺", "ℕ+", "ZPE", "ZEP", "Z+*", "Z*+", "ℤ⁺*", "ℤ*⁺", "ℤ+*", "ℤ*+"] },
+                // Logarithmic natural domains
+                { domain: Domain.NLog, shortcuts: ["NLOG", "ℕˡᵒᵍ", "ℕLOG"] },
+                // All integers domains
+                { domain: Domain.Z, shortcuts: ["Z", "ℤ"] },
+                // Zero-exclusive all integers domain
+                { domain: Domain.ZE, shortcuts: ["ZE", "Z*", "ℤ*"] },
+                // Negative integers domain
+                { domain: Domain.ZM, shortcuts: ["ZM", "Z-", "ℤ⁻", "ℤ-"] },
+                // Zero-exclusive negative integers domain
+                { domain: Domain.ZME, shortcuts: ["ZME", "ZEM", "Z-*", "Z*-", "ℤ⁻*", "ℤ*⁻", "ℤ-*", "ℤ*-"] },
+            ]
+
+            // Real domains
+            for(const { domain, shortcuts } of predefinedToCheck)
+                for(const shortcut of shortcuts)
+                    expect(parseDomainSimple(shortcut)).to.be.equal(domain)
+        })
+
+        it("returns parsed ranges", function() {
+            const parsedClosed = parseDomainSimple("[1;3]")
+            expect(parsedClosed.includes(1)).to.be.true
+            expect(parsedClosed.includes(2.4)).to.be.true
+            expect(parsedClosed.includes(3)).to.be.true
+            expect(parsedClosed.includes(3.01)).to.be.false
+            expect(parsedClosed.includes(0.99)).to.be.false
+            const parsedOpen = parseDomainSimple("]1;3[")
+            expect(parsedOpen.includes(1)).to.be.false
+            expect(parsedOpen.includes(3)).to.be.false
+            expect(parsedOpen.includes(2.4)).to.be.true
+            expect(parsedOpen.includes(1.01)).to.be.true
+            expect(parsedOpen.includes(2.99)).to.be.true
+            const parsedOpenBefore = parseDomainSimple("]1;3]")
+            expect(parsedOpenBefore.includes(1)).to.be.false
+            expect(parsedOpenBefore.includes(3)).to.be.true
+            expect(parsedOpenBefore.includes(2.4)).to.be.true
+            expect(parsedOpenBefore.includes(1.01)).to.be.true
+            expect(parsedOpenBefore.includes(3.01)).to.be.false
+            const parsedOpenAfter = parseDomainSimple("[1;3[")
+            expect(parsedOpenAfter.includes(1)).to.be.true
+            expect(parsedOpenAfter.includes(3)).to.be.false
+            expect(parsedOpenAfter.includes(2.4)).to.be.true
+            expect(parsedOpenAfter.includes(0.99)).to.be.false
+            expect(parsedOpenAfter.includes(2.99)).to.be.true
+        })
+
+        it("does not parse invalid ranges", function() {
+            expect(() => parseDomainSimple("]1;2;3[")).to.throw
+            expect(() => parseDomainSimple("]1,2;3[")).to.throw
+            expect(() => parseDomainSimple("](12);3[")).to.throw
+        })
+    })
+})
diff --git a/runtime-pyside6/LogarithmPlotter/qml/eu/ad5001/LogarithmPlotter/Popup/InsertCharacter.qml b/runtime-pyside6/LogarithmPlotter/qml/eu/ad5001/LogarithmPlotter/Popup/InsertCharacter.qml
index 7ef1794..9bf8f06 100644
--- a/runtime-pyside6/LogarithmPlotter/qml/eu/ad5001/LogarithmPlotter/Popup/InsertCharacter.qml
+++ b/runtime-pyside6/LogarithmPlotter/qml/eu/ad5001/LogarithmPlotter/Popup/InsertCharacter.qml
@@ -111,6 +111,8 @@ Popup {
                 model.append({ 'chr': chr })
             }
         }
+        
+        Keys.onEscapePressed: parent.close()
     }
     
     function setFocus() {
@@ -118,5 +120,4 @@ Popup {
         insertGrid.forceActiveFocus()
     }
     
-    Keys.onEscapePressed: close()
 }