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Instant-use add-on functions for the Wolfram Language
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Simulate the evaluation of a combinator expression as a multiway system
ResourceFunction["MultiwayCombinator"][rules,init,n] generates the results of n steps in the multiway evaluation of a combinator expression with the specified rules, starting from initial conditions init. | |
ResourceFunction["MultiwayCombinator"][rules,init,n,"prop"] gives the property "prop" for the specified multiway combinator expression evaluation. | |
ResourceFunction["MultiwayCombinator"][rules→sel,init,n,…] uses the function sel to select which of the events obtained at each step to include in the evaluation. |
"Sequential" | applies the first possible replacement (sequential substitution system) |
"Random" | applies a random replacement |
{"Random",n} | applies n randomly chosen replacements |
"AllStatesList" | the list of states generated at each successive step (default) |
"StatesCountsList" | the number of distinct states generated at each successive step |
"AllStatesListUnmerged" | the list of all states without any merging |
"PredecessorRulesList" | the list of states and their corresponding predecessor states at each successive step |
"EvolutionGraph" | graph formed by the evolution process, with no merging between different time steps |
"EvolutionGraphStructure" | evolution graph without labeling |
"EvolutionGraphFull" | graph formed by the evolution process, including equivalent events |
"EvolutionGraphFullStructure" | full evolution graph without labeling |
"EvolutionGraphUnmerged" | graph formed by the evolution process, with no merging of equivalent states |
"EvolutionGraphUnmergedStructure" | unmerged evolution graph without labeling |
"EvolutionGraphWeighted" | graph formed by the evolution process, with edges weighted by event multiplicity |
"EvolutionGraphWeightedStructure" | weighted evolution graph without labeling |
"StatesGraph" | graph of how each distinct state leads to other states |
"StatesGraphStructure" | states graph without labeling |
"AllEventsList" | the list of all events that occur at each successive step |
"EvolutionEventsGraph" | graph showing the evolution process with updating events explicitly included |
"EvolutionEventsGraphStructure" | evolution events graph without labeling |
"CausalGraph" | graph of all causal relations between updating events |
"CausalGraphStructure" | causal graph without labeling |
"EvolutionCausalGraph" | combined graph of evolution process and causal relationships between events |
"EvolutionCausalGraphStructure" | evolution causal graph without labeling |
"CausalGraphInstances" | list of distinct causal graphs for all possible choices of event sequences |
"CausalGraphStructureInstances" | causal graph instances without labeling |
"EvolutionCausalGraphInstances" | list of distinct evolution causal graphs for all possible choices of event sequences |
"EvolutionCausalGraphStructureInstances" | evolution causal graph instances without labeling |
"BranchPairsList" | list of all branch pairs (i.e. critical pairs) generated in the states graph |
"NewBranchPairsList" | list of all new branch pairs generated at each successive step |
"EvolutionBranchPairsList" | list of all branch pairs generated in the evolution graph |
"NewEvolutionBranchPairsList" | list of all new evolution branch pairs generated at each successive step |
"BranchPairEventsList" | list of all events yielding branch pairs |
"NewBranchPairEventsList" | list of all events yielding new branch pairs at each successive step |
"EvolutionBranchPairEventsList" | list of all events yielding evolution branch pairs |
"NewEvolutionBranchPairEventsList" | list of all events yielding new evolution branch pairs at each successive step |
"BranchialGraph" | graph of branch pair ancestry at a given step |
"BranchialGraphStructure" | branchial graph without labeling |
"AllStatesBranchialGraph" | graph of branch pair ancestry across all steps |
"AllStatesBranchialGraphStructure" | all states branchial graph without labeling |
"EvolutionBranchialGraph" | graph of evolution branch pair ancestry at a given step |
"EvolutionBranchialGraphStructure" | evolution branchial graph without labeling |
"AllStatesEvolutionBranchialGraph" | graph of evolution branch pair ancestry across all steps |
"AllStatesEvolutionBranchialGraphStructure" | all states evolution branchial graph without labeling |
"EventBranchialGraph" | graph of branch pair event ancestry at a given time step |
"EventBranchialGraphStructure" | event branchial graph without labeling |
"AllEventsBranchialGraph" | graph of branch pair event ancestry across all steps |
"AllEventsBranchialGraphStructure" | all events branchial graph without labeling |
"EvolutionEventBranchialGraph" | graph of evolution branch pair event ancestry at a given step |
"EvolutionEventBranchialGraphStructure" | evolution event branchial graph without labeling |
"AllEventsEvolutionBranchialGraph" | graph of evolution branch pair event ancestry across all steps |
"AllEventsEvolutionBranchialGraphStructure" | all events evolution branchial graph without labeling |
"BranchPairResolutionsList" | association of all resolved and unresolved branch pairs up to a given step |
"EvolutionBranchPairResolutionsList" | association of all resolved and unresolved evolution branch pairs up to a given step |
"CausalInvariantQ" | whether the system is causal invariant (all branch pairs converge) |
"EvolutionCausalInvariantQ" | whether the system is evolution causal invariant (all evolution branch pairs converge) |
"KnuthBendixCompletion" | list of Knuth–Bendix completion rules required to force causal invariance |
"EvolutionKnuthBendixCompletion" | list of Knuth–Bendix completion rules required to force evolution causal invariance |
"StateWeights" | list of weights for all vertices in the states graph |
"IncludeStepNumber" | False | whether to label states and events with their respective numbers |
"IncludeStateID" | False | whether to label states and events with unique IDs |
"IncludeInitializationEvents" | False | whether to include pseudoevents that set up initial conditions |
"IncludeEventInstances" | False | whether to show distinct updating events that connect the same states as separate edges |
"IncludeStateWeights" | False | whether to weight state vertices by their rate of occurrence at a particular time step |
"IncludeStatePathWeights" | False | whether to weight state vertices by the number of distinct evolution paths that lead to them |
"StateRenderingFunction" | Automatic | how to label states that appear in graphs |
"EventRenderingFunction" | Automatic | how to label events that appear in graphs |
MaxItems | Infinity | how many instances of a causal graph or evolution causal graph to return |
"GivePredecessors" | False | whether to label branch pairs with their predecessor state |
"GiveResolvents" | False | whether to label branch pairs with their resolvent state |
"IncludeSelfPairs" | False | whether to include trivial branch pairs |
"IncludeFullBranchialSpace" | False | whether to show all possible states in a given branchial graph |
"LineThickness" | 1 | absolute line thickness for graph edges |
Inherited | use the explicit vertex name as the label |
None | use no label for the vertex |
"shape" | use a shape from the VertexShapeFunction collection |
func | apply the function func to the name of the vertex |
Show basic multiway combinator evaluation for the fixed-point combinator (i.e. the Y-combinator):
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For the two-variable case:
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Generate a graph showing how each state is obtained from the others:
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Show the structure of the graph, without labels:
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Show multiway combinator evaluations for expressions in the S-K calculus:
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Show twelve steps without labels:
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Show a multiway combinator evaluation for an expression in the S-K-I calculus with a fixed-point (Y) combinator:
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Generate the list of all updating events applied at each step:
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Generate a graph of the evolution history, with updating events included:
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Show the structure of the graph, without labels:
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Generate the causal graph, showing dependencies between updating events:
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Note: the graph contains a disconnected component because the initial application of the fixed-point combinator rule is not causally dependent upon any previous event, and no subsequent event depends upon it.
Show the structure of the graph, without labels:
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Generate the evolution events graph, with causal connections included:
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Show the structure of the graph, without labels:
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Specify an event selection function that picks a random event at each step:
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Generate causal graphs for all possible choices of event sequences:
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Show the structures of the graphs, without labels:
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Generate the list of all branch pairs (i.e. critical pairs):
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Generate the association showing which branch pairs converged and which did not:
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Prove that the system is causal invariant (by the Church–Rosser property of combinatory logic):
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Generate a graph showing branch pair ancestry for an S-K combinator evaluation:
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Generate a graph showing branch pair event ancestry for the same evaluation:
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Prevent identical states from being merged by including step numbers and state IDs:
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List the states:
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Generate a graph of full evolution history, with all events included:
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Generate a graph of full evolution history, with no merging of equivalent states:
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Generate a graph of evolution history, with edges weighted by event multiplicity:
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Generate a states graph with vertices weighted by their rate of occurrence on each time step:
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Show the structure of the graph, without labels:
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Generate a states graph with vertices labelled by the number of distinct evolution paths that lead to them:
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Show the structure of the graph, without labels:
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MultiwayCombinator supports all forms of combinatory calculi, including the single-variable fixed-point (Y) combinator:
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The two-variable fixed-point (Y) combinator:
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The S-K calculus:
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The S-K-I calculus:
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Schönfinkel's B and C combinators:
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Due to the undecidability of the S-K-I combinatorial calculus, the following evaluation does not terminate at a normal form:
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MultiwayCombinator accepts both individual combinator rules and lists of combinator rules:
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MultiwayCombinator accepts both individual initial conditions and lists of initial conditions:
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Apply only the first possible event at each step:
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Apply the first and last possible events at each step:
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By default, states are labeled by their contents:
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Use no labeling for states:
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"StatesGraphStructure" yields the same result:
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Use raw state names as node labels:
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Use a named shape as each state label:
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By default, both states and events are labeled by their contents:
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Use no labels for states or events:
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"EvolutionEventsGraphStructure" yields an equivalent result:
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Use raw event expressions as their labels:
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By default, "AllEventsList" does not include initialization events:
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The option "IncludeInitializationEvents" allows one to override this default:
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Initialization events have special default rendering:
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Place arrows in the middle of edges:
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Generate an example of a multiway combinator evaluation:
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Force the initial state node to be at the top:
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By default, equivalent states are merged across all time steps:
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Merging of equivalent states across different time steps can be prevented by including step numbers:
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List the states:
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Merging of equivalent states at the same time step can be prevented by also including state IDs:
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List the states:
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Step numbers and IDs also apply to events:
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See the events:
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By default, multiple instances of equivalent updating events are merged in the states graph:
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Merging of equivalent events can be prevented by including event instances:
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Vertices of a states graph can be weighted by their relative rate of occurrence at each time step:
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Vertices can also be weighted by the number of distinct evolution paths that lead to them:
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By default, "CausalGraphInstances" returns all possible causal graphs:
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The number of causal graphs returned can be limited using MaxItems:
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By default, "BranchPairsList" returns only a list of branch pairs:
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Common predecessor states can be shown using "GivePredecessors":
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Similarly, "BranchPairResolutionsList" by default lists only resolved and unresolved branch pairs:
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Common resolvents of resolved branch pairs can be shown using "GiveResolvents":
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Show both common predecessors and common resolvents, where appropriate:
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By default, non-branch pair states are not shown as part of the branchial graph:
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They can be shown by using "IncludeFullBranchialSpace":
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This work is licensed under a Creative Commons Attribution 4.0 International License