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Mohit Gupta
@mohitacecode
just asking will that work for polycyclic group? beacuse the method we have now is checking whether the group G and H are PermutationGroup, FpGroup, FreeGroup
    if not isinstance(domain, (PermutationGroup, FpGroup, FreeGroup)):
raise TypeError("The domain must be a group")
if not isinstance(codomain, (PermutationGroup, FpGroup, FreeGroup)):
raise TypeError("The codomain must be a group")
Kalevi Suominen
@jksuom
Polycyclic groups are actually special fp-groups. They are formed from a free group by relators that are called pc_presentation.
Mohit Gupta
@mohitacecode
Okay understood will try to use it with polycyclic group
Mohit Gupta
@mohitacecode
Can you please tell how should I use this method with polycyclic group?
Mohit Gupta
@mohitacecode
should I consider looking for monoids and semigroups as a one of usefull idea as it was also mentioned by gaurav(@gxyd ) in gsoc 2016 but was'nt completed due to time constarint.
Kalevi Suominen
@jksuom
Monoids are more difficult to handle than groups. I don't know of any algorithms for them.
Mohit Gupta
@mohitacecode
Okay thanks for you response I will consider these things if i add it in proposal.
Mohit Gupta
@mohitacecode
Till now socle of a primitive permutation group is not implemented which can be further extended in calculating a chief series for a permuation group.I am considering this for adding it in my proposal.
After doing some research I have find some implementation of pseudo code for them.
Kalevi Suominen
@jksuom
The socle is not implemented for any finite group. That would probably be a good addition but maybe not easy.
Mohit Gupta
@mohitacecode
Thanks for your valuable suggestion kalevi :)
Mohit Gupta
@mohitacecode
I looked at the algorithm describes to see the difficulty of algorithm I find many of the required sub function already implemented in sympy.I am majorly concerned about the step 10 of the algorithm.
Here is the algorithm (http://huonw.github.io/honours-thesis.pdf) page no. 22.
Mohit Gupta
@mohitacecode
However theres also a naive algorithm which is very easy to implement it is also described in the book as follows:
socle is generated by minimal normal subgroups, one approach to finding it would be enumerating the normal subgroups, recording those that are minimal and then taking the subgroup that they generate. This could be done by iterating over group elements z ∈ G and taking the normal closures ⟨z^G⟩: every minimal normal subgroup is sure to appear in this list
Kalevi Suominen
@jksuom
I wonder how that would work with a permutation group of order >= 10^6.
Mohit Gupta
@mohitacecode
can we do something like if the order of group is greater than certain no. then we can go for the former algorithm
or something like if the group is primitive then we can go for former one because the later algorithm doesnt take any advantage of the group being primitive
Mohit Gupta
@mohitacecode
Good morning , kalevi
Currently conjugacy classes of permutation group are calculated using naive algorithm It can be improved by using random method presented here Pg-94 in book Groups ’93 Galway/St Andrews (https://ru.b-ok2.org/dl/703924/e2e2ff).
do implementation look feasible to you?
Kalevi Suominen
@jksuom
It is hard to say. There are very little details. Maybe the only way to find out is to implement it.
Mohit Gupta
@mohitacecode
Ohhkay... I will probable add it in my proposal.
Mohit Gupta
@mohitacecode
just one thing I wanna ask :
In pc_presentation(dictionary) which is created in the pc_relators method. since pc_presentation is a dictionary can any value associated with key be exponential something like {x:x**2}
Kalevi Suominen
@jksuom
I think that this should mean that x**2 is the identity.
Mohit Gupta
@mohitacecode
yes x**2 is the identity.
Mohit Gupta
@mohitacecode
Actually It is initialised using free_group.identity and after that it multiplied with the value of the perm_to_free (map pcgs gen to free_group gen) and then it is collected using collected_word. that is what x**2 is.
Divyanshu Thakur
@divyanshu132

can any value associated with key be exponential something like {x:x**2}

value mapped to a particular key can take any form but it should be collected and equivalent to lhs.

Mohit Gupta
@mohitacecode
okay got it..
Mohit Gupta
@mohitacecode
is there any way to find the representative of a conjugacy class?
Mohit Gupta
@mohitacecode

Hello everyone,