ConsiderSmallerPowermaps( tbl, prime_powermap,
prime )
ConsiderSmallerPowermaps( tbl,
prime_powermap, prime, "quick" )
improves the parametrized map prime_powermap (see chapter Maps and Parametrized Maps) that is an approximation of the prime-th powermap of the character table tbl:
If prime > tbl.orders[i] for a
class i, try to improve prime_powermap at class
i using that for g in class i, g_i^(prime)
= g_i^(prime mod tbl.orders[i]) holds;
so if the (prime mod tbl.orders[i])-th
powermap at class i is determined by the maps stored in tbl.powermap,
this information is used.
If "quick" is specified, only those classes are considered for
which prime_powermap is ambiguous.
If there are classes for which no image is possible, false is
returned, otherwise true.
Note: If tbl.orders is unbound,
true is returned without tests.
gap> t:= CharTable( "3.A6" );; init:= InitPowermap( t, 5 );;
gap> Indeterminateness( init );
4096
gap> ConsiderSmallerPowermaps( t, init, 5 );;
gap> Indeterminateness( init );
256
ConsiderSmallerPowermaps is used by Powermap Powermap.