In evolutionary computing such as genetic algorithms and genetic programming, propagation refers to the inheritance of characteristics of one generation by the next. For example, a schema is propagated if individuals in the current generation match it and so do those in the next generation. Those in the next generation may be (but don't have to be) children of parents who matched it.
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"Schema Propagation in Evolution Programs". http://www.ubka.uni-karlsruhe.de/vvv/2005/wiwi/4/4.pdf. 2006