Mitsch Order #1024
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Mitsch Order #1024
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gap/attributes/attr.gi
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| @@ -1052,6 +1052,188 @@ function(S) | |||
| end; | |||
| end); | |||
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| InstallMethod(KernelContainment, | |||
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Please:
- move this to
gap/elements/transf.g* - add tests
- add doc
- rename to
IsRefinementKernelOfTransformation - improve the error message using the format: "where, what went wrong, what was expected, and what was found"
| deg := DegreeOfTransformationSemigroup(S); | ||
| return | ||
| function(x, y) | ||
| # Only returns the correct answer if y is a regular element |
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Add check that y is regular.
Also what happens if x or y not in S?
gap/attributes/attr.gi
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| return out; | ||
| end); | ||
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| InstallMethod(MitschOrderOfTransformationSemigroup, |
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Remove this, unless it is actually much faster.
Co-authored-by: James Mitchell <[email protected]>
Co-authored-by: James Mitchell <[email protected]>
Co-authored-by: James Mitchell <[email protected]>
Co-authored-by: James Mitchell <[email protected]>
fingolfin
reviewed
Sep 5, 2024
Comment on lines
+1063
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| exists := false; | ||
| for i in [1 .. Size(class)] do | ||
| if class[i] ^ a = class[i] ^ b then | ||
| exists := true; | ||
| break; | ||
| fi; | ||
| od; | ||
| if not exists then | ||
| return false; | ||
| fi; |
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Not saying this is better, but I think you could also write it like this (assuming class is an iterable object):
Suggested change
| exists := false; | |
| for i in [1 .. Size(class)] do | |
| if class[i] ^ a = class[i] ^ b then | |
| exists := true; | |
| break; | |
| fi; | |
| od; | |
| if not exists then | |
| return false; | |
| fi; | |
| if ForAll(class, x -> x ^ a <> x ^ b) then | |
| return false; | |
| fi; |
fingolfin
reviewed
Sep 5, 2024
Comment on lines
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to
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| return ForAny(Elements(S), s -> x = x * s and x = y * s) and | ||
| ForAny(Elements(S), t -> t * y = x and t * x = x); |
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Aren't semigroups iterable? Because if they are, can't you just write
Suggested change
| return ForAny(Elements(S), s -> x = x * s and x = y * s) and | |
| ForAny(Elements(S), t -> t * y = x and t * x = x); | |
| return ForAny(S, s -> x = x * s and x = y * s) and | |
| ForAny(S, t -> t * y = x and t * x = x); |
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Add methods for finding the Mitsch order of a semigroup