Abstract
In [4] it is proved that the multiplicative group Fp⁎ is an automatically non-standard f-subgroup, here called a non-standard f-subgroup of the second type, for suitable f(x)∈Fp[x] whenever p is a prime with p>3 and p≡3(mod4). Here we extend this result to all odd non-Fermat primes p, and give two different proofs. Our first proof is an elaboration of that in [4], while the second proof leads to a general lower bound on the number of f-sequences that represent a non-standard f-subgroup of the second type; in certain very special cases, this lower bound is shown to be exact, although it is known not to be exact in general.
Original language | English |
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Article number | 102302 |
Number of pages | 18 |
Journal | Finite Fields And Their Applications |
Volume | 92 |
Early online date | 19 Sept 2023 |
DOIs | |
Publication status | Published - Dec 2023 |
Keywords
- Cyclotomic polynomial
- Fermat prime
- Finite field
- Linear recurrence relation
- Non-standard subgroup
- Second type
- Sophie-Germain prime