Arithmetic#

f + g: ModFrmElt, ModFrmElt -> ModFrmElt#

The sum of the modular forms \(f\) and \(g\).

f + g: ModFrmElt, RngSerPowElt -> RngSerPowElt#

The sum of the modular form \(f\) and the power series \(g\). The \(q\)-expansion of \(f\) must be coercible into the parent of \(g\). The sum \(g+f\) is also defined, as are the differences \(f-g\) and \(g-f\).

f - g: ModFrmElt, ModFrmElt -> ModFrmElt#

The difference of the modular forms \(f\) and \(g\).

a * f: RngElt, ModFrmElt -> ModFrmElt#

The product of the scalar \(a\) and the modular form \(f\).

f / a: ModFrmElt, RngElt -> ModFrmElt#

The product of the scalar \(1/a\) and the modular form \(f\).

f ^ n: ModFrmElt, RngIntElt -> ModFrmElt#

The power \(f^n\) of the modular form \(f\), where \(n\geq 1\) is an integer.

f * g: ModFrmElt, ModFrmElt -> ModFrmElt#

The product of the modular forms \(f\) and \(g\). The only condition is that the base fields of \(f\) and \(g\) be the same. The weight of f*g is the sum of the weights of \(f\) and \(g\).

Example: Arithmetic (ex-061f7d)#
> M2 := ModularForms(Gamma0(11), 2);
> f := M2.1;
> g := M2.2;
> f;
1 + 12*q^2 + 12*q^3 + 12*q^4 + 12*q^5 + 24*q^6 + 24*q^7 + O(q^8)
> g;
q - 2*q^2 - q^3 + 2*q^4 + q^5 + 2*q^6 - 2*q^7 + O(q^8)
> f+g;
1 + q + 10*q^2 + 11*q^3 + 14*q^4 + 13*q^5 + 26*q^6 + 22*q^7 + O(q^8)
> 2*f;
2 + 24*q^2 + 24*q^3 + 24*q^4 + 24*q^5 + 48*q^6 + 48*q^7 + O(q^8)
> MQ,phi := BaseExtend(M2, RationalField());
> phi(2*f)/2;
1 + 12*q^2 + 12*q^3 + 12*q^4 + 12*q^5 + 24*q^6 + 24*q^7 + O(q^8)
> f^2;
1 + 24*q^2 + 24*q^3 + 168*q^4 + 312*q^5 + 480*q^6 + 624*q^7 + O(q^8)
> Parent($1);
Space of modular forms on Gamma_0(11) of weight 4 and dimension 4 over
Integer Ring.
> M3 := ModularForms([DirichletGroup(11).1], 3); M3;
Space of modular forms on Gamma_1(11) with character all conjugates of
[$.1], weight 3, and dimension 3 over Integer Ring.
> M3.1*f;
1 + 12*q^2 + 2*q^3 + 6*q^4 - 126*q^5 - 168*q^6 - 384*q^7 + O(q^8)
> Parent($1);
Space of modular forms on Gamma_1(11) of weight 5 and dimension 25
over Integer Ring.

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