diff --git a/Sources/apk/Common/ApkRequirement.swift b/Sources/apk/Common/ApkRequirement.swift
index 244ca1b..29f99d1 100644
--- a/Sources/apk/Common/ApkRequirement.swift
+++ b/Sources/apk/Common/ApkRequirement.swift
@@ -5,8 +5,16 @@
 
 import Foundation
 
-internal struct ApkRequirement {
-  static func extract(blob extract: String) throws(ParseError) -> (String, ApkVersionSpecification) {
+internal struct ApkRequirement: Hashable {
+  let name: String
+  let versionSpec: ApkVersionSpecification
+
+  init(name: String, spec: ApkVersionSpecification) {
+    self.name = name
+    self.versionSpec = spec
+  }
+
+  init(extract: String) throws(ParseError) {
     var comparer: ComparatorBits = []
     var dependStr = extract[...]
     let nameEnd: String.Index, versionStart: String.Index
@@ -30,7 +38,7 @@ internal struct ApkRequirement {
       }
       (nameEnd, versionStart) = (range.lowerBound, range.upperBound)
     } else {
-      // 
+      // Lack of conflict flag indicates any version
       if !comparer.contains(.conflict) {
         comparer.formUnion(.any)
       }
@@ -38,9 +46,18 @@ internal struct ApkRequirement {
     }
 
     // Parse version specification
-    let spec = try ApkVersionSpecification(comparer, version: dependStr[versionStart...])
-    let name = String(dependStr[..<nameEnd])
-    return (name, spec)
+    self.versionSpec = try ApkVersionSpecification(comparer, version: dependStr[versionStart...])
+    self.name = String(dependStr[..<nameEnd])
+  }
+}
+
+extension ApkRequirement: CustomStringConvertible {
+  var description: String {
+    switch self.versionSpec {
+    case .any: self.name
+    case .conflict: "!\(self.name)"
+    case .constraint(let op, let version): "\(self.name)\(op)\(version)"
+    }
   }
 }
 
diff --git a/Sources/apk/Graph/ApkPackageGraph.swift b/Sources/apk/Graph/ApkPackageGraph.swift
new file mode 100644
index 0000000..c0ea6cf
--- /dev/null
+++ b/Sources/apk/Graph/ApkPackageGraph.swift
@@ -0,0 +1,64 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+class ApkPackageGraph {
+  let pkgIndex: ApkIndex
+
+  private var _nodes = [ApkPackageGraphNode]()
+
+  var nodes: [ApkPackageGraphNode] { self._nodes }
+  var shallowIsolates: [ApkPackageGraphNode] { self._nodes.filter(\.parents.isEmpty) }
+  var deepIsolates: [ApkPackageGraphNode] { self._nodes.filter(\.children.isEmpty) }
+
+  init(index: ApkIndex) {
+    self.pkgIndex = index
+  }
+
+  func buildGraphNode() {
+    var provides = [String: Int]()
+
+    for (idx, package) in self.pkgIndex.packages.enumerated() {
+      provides[package.name] = idx
+      for provision in package.provides {
+        provides[provision.name] = idx
+      }
+    }
+
+    for package in pkgIndex.packages {
+      self._nodes.append(.init(
+        package: package,
+        children: package.dependencies.compactMap { dependency in
+          guard let id = provides[dependency.requirement.name] else {
+            return nil
+          }
+          return .init(self, id: id, constraint: .dep(version: dependency.requirement.versionSpec))
+        } + package.provides.compactMap { provision in
+          guard let id = provides[provision.name] else {
+            return nil
+          }
+          return .init(self, id: id, constraint: .provision)
+        } + package.installIf.compactMap { installIf in
+          guard let id = provides[installIf.requirement.name] else {
+            return nil
+          }
+          return .init(self, id: id, constraint: .installIf(version: installIf.requirement.versionSpec ))
+        }
+      ))
+    }
+
+    var reverseDependencies = [ApkIndexRequirementRef: [ApkIndexRequirementRef]]()
+    for (index, node) in self._nodes.enumerated() {
+      for child in node.children {
+        reverseDependencies[child, default: []].append(
+          .init(self, id: index, constraint: child.constraint)
+        )
+      }
+    }
+
+    for (ref, parents) in reverseDependencies {
+      self._nodes[ref.packageID].parents = parents
+    }
+  }
+}
diff --git a/Sources/apk/Graph/ApkPackageGraphNode.swift b/Sources/apk/Graph/ApkPackageGraphNode.swift
new file mode 100644
index 0000000..034b0b0
--- /dev/null
+++ b/Sources/apk/Graph/ApkPackageGraphNode.swift
@@ -0,0 +1,35 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+
+class ApkPackageGraphNode {
+  private weak var graph: ApkPackageGraph!
+  let package: ApkIndexPackage
+
+  //private var _parents = NSHashTable<ApkPackageGraphNode>.weakObjects()
+  //private var _children = NSHashTable<ApkPackageGraphNode>.weakObjects()
+  var parents = [ApkIndexRequirementRef]()
+  var children: [ApkIndexRequirementRef]
+
+  internal init(package: ApkIndexPackage, children: [ApkIndexRequirementRef]) {
+    self.package = package
+    self.children = children
+  }
+}
+
+extension ApkPackageGraphNode: CustomStringConvertible {
+  var description: String {
+    var result = "node[\(self.package.name)]"
+    if !self.parents.isEmpty {
+      result += ", parents[\(self.parents.lazy.map(\.description).joined(separator: ", "))]"
+    }
+    if !self.children.isEmpty {
+      result += ", children[\(self.children.lazy.map(\.description).joined(separator: ", "))]"
+      
+    }
+    return result
+  }
+}
diff --git a/Sources/apk/Index/ApkIndexDependency.swift b/Sources/apk/Index/ApkIndexDependency.swift
index 6514e35..740cc0f 100644
--- a/Sources/apk/Index/ApkIndexDependency.swift
+++ b/Sources/apk/Index/ApkIndexDependency.swift
@@ -5,22 +5,10 @@
 
 import Foundation
 
-struct ApkIndexDependency: ApkIndexRequirementRef {
-  let name: String
-  let versionSpec: ApkVersionSpecification
+struct ApkIndexDependency: Hashable {
+  let requirement: ApkRequirement
 
-  init(name: String, version spec: ApkVersionSpecification) {
-    self.name = name
-    self.versionSpec = spec
-  }
-}
-
-extension ApkIndexDependency: CustomStringConvertible {
-  var description: String {
-    switch self.versionSpec {
-    case .any: self.name
-    case .conflict: "!\(self.name)"
-    case .constraint(let op, let version): "\(self.name)\(op)\(version)"
-    }
+  init(requirement: ApkRequirement) {
+    self.requirement = requirement
   }
 }
diff --git a/Sources/apk/Index/ApkIndexInstallIf.swift b/Sources/apk/Index/ApkIndexInstallIf.swift
index fcade26..7cd382b 100644
--- a/Sources/apk/Index/ApkIndexInstallIf.swift
+++ b/Sources/apk/Index/ApkIndexInstallIf.swift
@@ -3,12 +3,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-struct ApkIndexInstallIf: ApkIndexRequirementRef {
-  let name: String
-  let versionSpec: ApkVersionSpecification
+struct ApkIndexInstallIf: Hashable {
+  let requirement: ApkRequirement
 
-  init(name: String, version spec: ApkVersionSpecification) {
-    self.name = name
-    self.versionSpec = spec
+  init(requirement: ApkRequirement) {
+    self.requirement = requirement
   }
 }
diff --git a/Sources/apk/Index/ApkIndexPackage.swift b/Sources/apk/Index/ApkIndexPackage.swift
index daa0765..1959637 100644
--- a/Sources/apk/Index/ApkIndexPackage.swift
+++ b/Sources/apk/Index/ApkIndexPackage.swift
@@ -5,7 +5,7 @@
 
 import Foundation
 
-struct ApkIndexPackage: ApkIndexRequirementRef {
+struct ApkIndexPackage: Hashable {
   let indexChecksum: ApkIndexDigest
   let name: String
   let version: String
@@ -74,8 +74,10 @@ extension ApkIndexPackage {
       case "A":
         architecture = record.value
       case "D":
-        do { dependencies = try ApkIndexDependency.extract(record.value) }
-        catch { throw .badValue(key: record.key) }
+        do {
+          dependencies = try record.value.components(separatedBy: " ")
+            .map { .init(requirement: try .init(extract: $0)) }
+        } catch { throw .badValue(key: record.key) }
       case "C":
         guard let digest = ApkIndexDigest(decode: record.value) else {
           throw .badValue(key: record.key)
@@ -92,11 +94,15 @@ extension ApkIndexPackage {
         }
         installedSize = value
       case "p":
-        do { provides = try ApkIndexProvides.extract(record.value) }
-        catch { throw .badValue(key: record.key) }
+        do {
+          provides = try record.value.components(separatedBy: " ")
+            .map { .init(requirement: try .init(extract: $0)) }
+        } catch { throw .badValue(key: record.key) }
       case "i":
-        do { installIf = try ApkIndexInstallIf.extract(record.value) }
-        catch { throw .badValue(key: record.key) }
+        do {
+          installIf = try record.value.components(separatedBy: " ")
+            .map { .init(requirement: try .init(extract: $0)) }
+        } catch { throw .badValue(key: record.key) }
       case "o":
         origin = record.value
       case "m":
@@ -191,13 +197,13 @@ extension ApkIndexPackage: CustomStringConvertible {
     s += "provider prio:  \(providerPrio)\n"
     }
     if !self.dependencies.isEmpty {
-    s += "dependencies: - \(self.dependencies.map(String.init).joined(separator: " "))\n"
+    s += "dependencies: - \(self.dependencies.map(\.requirement.description).joined(separator: " "))\n"
     }
     if !self.provides.isEmpty {
-    s += "provides: ----- \(self.provides.map { $0.name }.joined(separator: " "))\n"
+    s += "provides: ----- \(self.provides.map(\.name).joined(separator: " "))\n"
     }
     if !self.installIf.isEmpty {
-    s += "install if: --- \(self.installIf.map { $0.name }.joined(separator: " "))\n"
+    s += "install if: --- \(self.installIf.map(\.requirement.description).joined(separator: " "))\n"
     }
     return s
   }
diff --git a/Sources/apk/Index/ApkIndexProvides.swift b/Sources/apk/Index/ApkIndexProvides.swift
index 0e86438..759ee11 100644
--- a/Sources/apk/Index/ApkIndexProvides.swift
+++ b/Sources/apk/Index/ApkIndexProvides.swift
@@ -3,10 +3,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-struct ApkIndexProvides: ApkIndexRequirementRef {
+struct ApkIndexProvides: Hashable {
   let name: String
 
-  init(name: String, version _: ApkVersionSpecification) {
-    self.name = name
+  init(requirement: ApkRequirement) {
+    self.name = requirement.name
   }
 }
diff --git a/Sources/apk/Index/ApkIndexRequirementRef.swift b/Sources/apk/Index/ApkIndexRequirementRef.swift
index 4b527bd..e0c1ec4 100644
--- a/Sources/apk/Index/ApkIndexRequirementRef.swift
+++ b/Sources/apk/Index/ApkIndexRequirementRef.swift
@@ -3,24 +3,58 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-protocol ApkIndexRequirementRef: Equatable, Hashable {
-  var name: String { get }
-  var invert: Bool { get }
+struct ApkIndexRequirementRef {
+  private weak var _graph: ApkPackageGraph?
 
-  init(name: String, version spec: ApkVersionSpecification)
+  let packageID: Int
+  let constraint: Constraint
 
-  func satisfied(by other: ApkIndexPackage) -> Bool
+  init(_ graph: ApkPackageGraph, id: Int, constraint: Constraint) {
+    self._graph = graph
+    self.packageID = id
+    self.constraint = constraint
+  }
+
+  var package: ApkIndexPackage {
+    self._graph!.pkgIndex.packages[self.packageID]
+  }
+
+  func satisfied(by other: ApkRequirement) -> Bool {
+    true
+  }
+}
+
+extension ApkIndexRequirementRef: Equatable, Hashable {
+  static func == (lhs: Self, rhs: Self) -> Bool {
+    lhs.packageID == rhs.packageID && lhs.constraint == rhs.constraint
+  }
+
+  func hash(into hasher: inout Hasher) {
+    self.packageID.hash(into: &hasher)
+    self.constraint.hash(into: &hasher)
+  }
 }
 
 extension ApkIndexRequirementRef {
-  var invert: Bool { false }
-  func satisfied(by _: ApkIndexPackage) -> Bool { true }
-
-  static func extract<T: ApkIndexRequirementRef>(_ blob: String) throws(ApkRequirement.ParseError) -> [T] {
-    return try blob.components(separatedBy: " ")
-      .map { token throws(ApkRequirement.ParseError) in
-        let (name, versionSpec) = try ApkRequirement.extract(blob: token)
-        return .init(name: name, version: versionSpec)
-      }
+  enum Constraint: Hashable {
+    case dep(version: ApkVersionSpecification)
+    case provision
+    case installIf(version: ApkVersionSpecification)
+  }
+}
+
+extension ApkIndexRequirementRef: CustomStringConvertible {
+  var description: String {
+    guard let package = self._graph?.pkgIndex.packages[self.packageID] else {
+      return String()
+    }
+    return switch self.constraint {
+    case .dep(let version):
+      "dep=\(ApkRequirement(name: package.name, spec: version))"
+    case .provision:
+      "provides=\(package.name)"
+    case .installIf(let version):
+      "installIf=\(ApkRequirement(name: package.name, spec: version))"
+    }
   }
 }
diff --git a/Sources/apk/Index/ApkIndexUpdate.swift b/Sources/apk/Index/ApkIndexUpdate.swift
index b3b618f..19f1557 100644
--- a/Sources/apk/Index/ApkIndexUpdate.swift
+++ b/Sources/apk/Index/ApkIndexUpdate.swift
@@ -13,11 +13,11 @@ public struct ApkIndexUpdater {
 
   public init() {
     self.repositories = [
-      "https://dl-cdn.alpinelinux.org/alpine/v3.21/main",
-      "https://dl-cdn.alpinelinux.org/alpine/edge/community"
+      "https://dl-cdn.alpinelinux.org/alpine/v3.20/main",
+      "https://dl-cdn.alpinelinux.org/alpine/v3.20/community"
     ]
     // other archs: "armhf", "armv7", "loongarch64", "ppc64le", "riscv64", "s390x", "x86"
-    self.architectures = [ "aarch64", "x86_64" ]
+    self.architectures = [ "aarch64" /*, "x86_64" */ ]
   }
 
   public func update() {
@@ -41,14 +41,23 @@ public struct ApkIndexUpdater {
       }
     }
 
-    let index: ApkIndex
+    let graph: ApkPackageGraph
     do {
       let tables = try repositories.map { try readIndex(URL(filePath: $0.localName)) }
-      index = ApkIndex.merge(tables)
-      try index.description.write(to: URL(fileURLWithPath: "packages.txt"), atomically: false, encoding: .utf8)
+      graph = ApkPackageGraph(index: ApkIndex.merge(tables))
+      graph.buildGraphNode()
+
+      try graph.pkgIndex.description.write(to: URL(filePath: "packages.txt"), atomically: false, encoding: .utf8)
     } catch {
       fatalError(error.localizedDescription)
     }
+
+    if var out = TextFileWriter(URL(filePath: "shallowIsolates.txt")) {
+      for node in graph.shallowIsolates { print(node, to: &out) }
+    }
+    if var out = TextFileWriter(URL(filePath: "deepIsolates.txt")) {
+      for node in graph.deepIsolates { print(node, to: &out) }
+    }
   }
 
   private func readIndex(_ indexURL: URL) throws -> ApkIndex {
diff --git a/Sources/apk/Utility/TextFileWriter.swift b/Sources/apk/Utility/TextFileWriter.swift
new file mode 100644
index 0000000..0a3d1a4
--- /dev/null
+++ b/Sources/apk/Utility/TextFileWriter.swift
@@ -0,0 +1,28 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+
+struct TextFileWriter: TextOutputStream {
+  private var _hnd: FileHandle
+
+  init?(_ to: URL) {
+    let file = open(to.path(), O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, 0o644)
+    guard file >= 0 else {
+      return nil
+    }
+    self._hnd = FileHandle(fileDescriptor: file, closeOnDealloc: true)
+  }
+
+  mutating func write(_ string: String) {
+    if let data = string.data(using: .utf8) {
+      try? self._hnd.write(contentsOf: data)
+    }
+  }
+
+  mutating func close() throws {
+    try self._hnd.close()
+  }
+}