Cyclic or acyclic ethers are required to stabilize the organomagnesium compound. Equivalently, a forest is an undirected acyclic graph. Angle strain typically affects cyclic molecules, which lack the flexibility of acyclic molecules. The saturated heterocycles behave like the acyclic derivatives. Reverse postordering produces a topological sorting of any directed acyclic graph. Topological sorting of dependencies depends on the dependency graph being a directed acyclic graph (DAG). A monosaccharide can switch between acyclic (open-chain) form and a cyclic form. An acyclic alkyl has the general formula of CH. Biological ontologies are directed acyclic graphs of controlled vocabularies. Each computation dataflow graph is a list of nodes that form an acyclic graph. RPL creates a topology similar to a tree (DAG or directed acyclic graph). Farnesol is a natural 15-carbon organic compound which is an acyclic sesquiterpene alcohol. Symbolic expressions are stored in memory as directed acyclic graphs. The graph enumeration problem of counting directed acyclic graphs was studied by . Monoterpenes may be linear (acyclic) or contain rings.