Stage 7.2: high-yield scheme (Ponzi), prediction/manipulation docs

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Decentralized.Domain/Ponzi.cs

@@ -0,0 +1,80 @@
+using System;
+
+namespace Decentralized.Domain
+{
+    /// <summary>夜间发生的事。Kind：collapse（付不出利息，挤兑）/ reported（被举报）；Amount 是被没收的池子。</summary>
+    public sealed class PonziEvent
+    {
+        public string Kind;
+        public double Amount;
+    }
+
+    /// <summary>
+    /// 高息理财（庞氏）：玩家定一个日息，下层的人按日息和下层声望往池子里存 CRC。每晚先拿新存入的钱付利息，不够的从 Poinbase 账户的 CRC 补，
+    /// 补不上就挤兑崩盘；池子越大、日息越高越容易被举报，被举报同样崩盘。崩盘时池子被没收；玩家也可以随时卷走池子（污点全额）。
+    /// 每个存档只能开一次。
+    /// </summary>
+    public sealed class Ponzi
+    {
+        public bool Open, Done;
+        public double Rate, Pool, OwnPaid, AdCost, Inflow;
+        public int OpenDay = -1;
+
+        public static double Cap(int day) => Tuning.PonziCap0 + Tuning.PonziCapPerDay * day;
+
+        /// <summary>每晚新存入（均值）：基数随天数，日息高于 4% 时按指数放大，下层声望越高越多。</summary>
+        public static double InflowMean(int day, double rate, int lowerRep) =>
+            (Tuning.PonziBase0 + Tuning.PonziBasePerDay * day) * Math.Pow(rate / 0.04, Tuning.PonziRateExp) * Math.Max(0.3, Math.Min(1.5, 0.5 + lowerRep / 100.0));
+
+        public static double ReportChance(double rate, double pool, int day) =>
+            Math.Min(0.9, Tuning.PonziReport0 + Tuning.PonziReportRate * rate + Tuning.PonziReportSize * Math.Min(1, pool / Cap(day)));
+
+        public bool CanOpen(int day) => !Open && !Done && day >= Tuning.PonziMinDay;
+
+        /// <summary>开张：宣传费从账户的 CRC 里扣。</summary>
+        public bool Start(Wallet acct, double rate, int day)
+        {
+            if (!CanOpen(day) || acct.Avail(Assets.CRC) + 1e-9 < Tuning.PonziAdCost) return false;
+            acct.Add(Assets.CRC, -Tuning.PonziAdCost);
+            Open = true; Rate = rate; Pool = 0; OwnPaid = 0; AdCost = Tuning.PonziAdCost; OpenDay = day;
+            return true;
+        }
+
+        /// <summary>夜间结算。返回崩盘 / 被举报事件（没有事就返回 null）。</summary>
+        public PonziEvent Night(int day, int lowerRep, Wallet acct, Rng rng)
+        {
+            if (!Open) return null;
+            double mean = InflowMean(day, Rate, lowerRep);
+            double inflow = Math.Min(Cap(day) - Pool, mean * rng.Range(0.6, 1.4));
+            inflow = Math.Max(0, inflow); Inflow = inflow;
+            double interest = Pool * Rate;
+            double fromInflow = Math.Min(interest, inflow), rest = interest - fromInflow;
+            if (rest > acct.Avail(Assets.CRC) + 1e-9)
+            {
+                var ev = new PonziEvent { Kind = "collapse", Amount = Pool + inflow - fromInflow };
+                Open = false; Done = true; Pool = 0;
+                return ev;
+            }
+            if (rest > 0) { acct.Add(Assets.CRC, -rest); OwnPaid += rest; }
+            Pool += inflow - fromInflow;
+            Pool -= Pool * Tuning.PonziWithdraw;
+            if (rng.Chance(ReportChance(Rate, Pool, day)))
+            {
+                var ev = new PonziEvent { Kind = "reported", Amount = Pool };
+                Open = false; Done = true; Pool = 0;
+                return ev;
+            }
+            return null;
+        }
+
+        /// <summary>卷走：池子全部进账户，污点全额（骗局所得）。返回卷走的数额。</summary>
+        public double Rug(Wallet acct)
+        {
+            if (!Open) return 0;
+            double take = Pool;
+            acct.Add(Assets.CRC, take); acct.Taint += take;
+            Open = false; Done = true; Pool = 0;
+            return take;
+        }
+    }
+}

src/Decentralized.Domain/Tuning.cs

@@ -208,6 +208,16 @@ namespace Decentralized.Domain
         public const double ManipFree = 0.02, ManipBase = 0.25, ManipSlope = 6, ManipMax = 0.95;
         public const int ManipFreezeDays = 3;
 
+        /// <summary>高息理财（庞氏）：第几天起开放、开张的宣传费（CRC）、可选日息、每晚新存入的基数（随天数）和对日息的敏感指数、
+        /// 池子上限（随天数）、每晚被取走的比例、每晚被举报概率（基础 + 日息系数 + 池子占上限的比例系数）、卷走或崩盘时记的罪证。</summary>
+        public const int PonziMinDay = 15;
+        public const double PonziAdCost = 800;
+        public static readonly double[] PonziRates = { 0.02, 0.04, 0.06, 0.08, 0.10 };
+        public const double PonziBase0 = 300, PonziBasePerDay = 15, PonziRateExp = 1.5;
+        public const double PonziCap0 = 6000, PonziCapPerDay = 200, PonziWithdraw = 0.03;
+        public const double PonziReport0 = 0.02, PonziReportRate = 0.5, PonziReportSize = 0.04;
+        public const double PonziCrime = 1200;
+
         /// <summary>主交易对（信用点一侧）的深度随天数增长。</summary>
         public static double PoolDepth(int day) => PoolDepth0 * (1 + day / 60.0);
     }