/// <summary>
        /// This execution of the delta rule CAN remove single selections
        /// from a market if they haven't changes since last time.
        /// </summary>
        /// <param name="fixture"></param>
        /// <param name="mkt"></param>
        /// <param name="state"></param>
        /// <param name="intent"></param>
        private void ApplyDeltaRule_RemovingSelections(Fixture fixture, Market mkt, IMarketState state, MarketRuleResultIntent intent)
        {
            List <Selection> seln_changed = new List <Selection>();

            foreach (var seln in mkt.Selections)
            {
                // if we don't have the selection state, we can't
                // determine what has changed within the selection,
                // so we assume that everything has changed
                if (state.HasSelection(seln.Id) && state[seln.Id].IsEquivalentTo(seln, true))
                {
                    continue;
                }

                _logger.DebugFormat("market rule={0} => {1} of {2} has changed", Name, seln, mkt);
                seln_changed.Add(seln);
            }


            if (seln_changed.Count == 0)
            {
                if (state.IsEquivalentTo(mkt, true, false))
                {
                    _logger.DebugFormat("market rule={0} => {1} of {2} marked as removable", Name, mkt, fixture);
                    intent.MarkAsRemovable(mkt);
                }
                else
                {
                    Action <Market>      action = x => x.Selections.Clear();
                    MarketRuleEditIntent edit   = new MarketRuleEditIntent(action, MarketRuleEditIntent.OperationType.REMOVE_SELECTIONS);
                    intent.EditMarket(mkt, edit);
                }
            }
            else
            {
                if (seln_changed.Count() != mkt.Selections.Count())
                {
                    Action <Market>      action = x => x.Selections.RemoveAll(y => !seln_changed.Contains(y));
                    MarketRuleEditIntent edit   = new MarketRuleEditIntent(action, MarketRuleEditIntent.OperationType.REMOVE_SELECTIONS);
                    intent.EditMarket(mkt, edit);
                }
            }
        }
        /// <summary>
        /// This execution of the delta rule CAN remove single selections
        /// from a market if they haven't changes since last time.
        /// </summary>
        /// <param name="fixture"></param>
        /// <param name="mkt"></param>
        /// <param name="state"></param>
        /// <param name="intent"></param>
        private void ApplyDeltaRule_RemovingSelections(Fixture fixture, Market mkt, IMarketState state, MarketRuleResultIntent intent)
        {

            List<Selection> seln_changed = new List<Selection>();
            foreach (var seln in mkt.Selections)
            {
                // if we don't have the selection state, we can't
                // determine what has changed within the selection,
                // so we assume that everything has changed
                if (state.HasSelection(seln.Id) && state[seln.Id].IsEquivalentTo(seln, true))
                    continue;

                _logger.DebugFormat("market rule={0} => {1} of {2} has changed", Name, seln, mkt);
                seln_changed.Add(seln);
            }


            if (seln_changed.Count == 0)
            {
                if (state.IsEquivalentTo(mkt, true, false))
                {
                    _logger.DebugFormat("market rule={0} => {1} of {2} marked as removable", Name, mkt, fixture);
                    intent.MarkAsRemovable(mkt);
                }
                else
                {
                    Action<Market> action = x => x.Selections.Clear();
                    MarketRuleEditIntent edit = new MarketRuleEditIntent(action, MarketRuleEditIntent.OperationType.REMOVE_SELECTIONS);
                    intent.EditMarket(mkt, edit);
                }
            }
            else
            {
                if (seln_changed.Count() != mkt.Selections.Count())
                {
                    Action<Market> action = x => x.Selections.RemoveAll(y => !seln_changed.Contains(y));
                    MarketRuleEditIntent edit = new MarketRuleEditIntent(action, MarketRuleEditIntent.OperationType.REMOVE_SELECTIONS);
                    intent.EditMarket(mkt, edit);
                }
            }
        }