First implementation (#1)

Reviewed-on: #1

schemas/mathml.schema.json

@@ -0,0 +1,52 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://paperspec.scient.ing/schemas/mathml.schema.json",
+  "title": "Derived MathML",
+  "description": "One line of derived/mathml.jsonl: MathML made by a pinned tool; never authoritative; spec/12-package.md.",
+  "type": "object",
+  "properties": {
+    "node": {
+      "$ref": "common.schema.json#/$defs/nodeId"
+    },
+    "run": {
+      "anyOf": [
+        {
+          "type": "integer",
+          "minimum": 0
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "tool": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "type": "string",
+          "minLength": 1
+        },
+        "version": {
+          "type": "string",
+          "minLength": 1
+        }
+      },
+      "required": [
+        "name",
+        "version"
+      ],
+      "additionalProperties": false
+    },
+    "mathml": {
+      "type": "string",
+      "pattern": "^<math[ >]"
+    }
+  },
+  "required": [
+    "node",
+    "run",
+    "tool",
+    "mathml"
+  ],
+  "additionalProperties": false
+}