Galois Theory
Test your understanding of Galois Theory, a branch of abstract algebra that studies field extensions and their automorphisms.
Questions
Question 1 Multiple Choice (Single Answer)
What is the fundamental theorem of Galois theory?
- Every finite extension of a field is normal.
- Every finite normal extension of a field is separable.
- The Galois group of a finite extension of a field is isomorphic to the group of automorphisms of the extension.
- All of the above.
Question 2 Multiple Choice (Single Answer)
What is a Galois extension?
- A finite extension of a field that is normal and separable.
- A finite extension of a field that is normal but not necessarily separable.
- A finite extension of a field that is separable but not necessarily normal.
- A finite extension of a field that is neither normal nor separable.
Question 3 Multiple Choice (Single Answer)
What is the Galois group of a field extension?
- The group of all automorphisms of the extension.
- The group of all automorphisms of the extension that fix the base field.
- The group of all automorphisms of the extension that fix the base field and its subfields.
- The group of all automorphisms of the extension that fix the base field and its subfields and their subfields.
Question 4 Multiple Choice (Single Answer)
What is the order of the Galois group of a Galois extension?
- The degree of the extension.
- The number of elements in the extension.
- The number of automorphisms of the extension.
- The number of automorphisms of the extension that fix the base field.
Question 5 Multiple Choice (Single Answer)
What is the solvability of a polynomial?
- The ability to express its roots in terms of radicals.
- The ability to express its roots in terms of elementary functions.
- The ability to express its roots in terms of algebraic functions.
- The ability to express its roots in terms of transcendental functions.
Question 6 Multiple Choice (Single Answer)
What is the Galois group of a polynomial?
- The group of all automorphisms of the splitting field of the polynomial.
- The group of all automorphisms of the splitting field of the polynomial that fix the base field.
- The group of all automorphisms of the splitting field of the polynomial that fix the base field and its subfields.
- The group of all automorphisms of the splitting field of the polynomial that fix the base field and its subfields and their subfields.
Question 7 Multiple Choice (Single Answer)
What is the irreducibility of a polynomial?
- The inability to factor the polynomial into a product of two non-constant polynomials.
- The inability to factor the polynomial into a product of two non-linear polynomials.
- The inability to factor the polynomial into a product of two non-quadratic polynomials.
- The inability to factor the polynomial into a product of two non-cubic polynomials.
Question 8 Multiple Choice (Single Answer)
What is the Eisenstein criterion for irreducibility?
- If a polynomial has an integer coefficient, a leading coefficient of 1, and a constant term that is not divisible by the leading coefficient, then it is irreducible over the integers.
- If a polynomial has a rational coefficient, a leading coefficient of 1, and a constant term that is not divisible by the leading coefficient, then it is irreducible over the rationals.
- If a polynomial has a real coefficient, a leading coefficient of 1, and a constant term that is not divisible by the leading coefficient, then it is irreducible over the reals.
- If a polynomial has a complex coefficient, a leading coefficient of 1, and a constant term that is not divisible by the leading coefficient, then it is irreducible over the complex numbers.
Question 9 Multiple Choice (Single Answer)
What is the primitive element theorem?
- Every finite field extension has a primitive element.
- Every finite Galois extension has a primitive element.
- Every finite normal extension has a primitive element.
- Every finite separable extension has a primitive element.
Question 10 Multiple Choice (Single Answer)
What is the Kronecker-Weber theorem?
- Every abelian extension of the rationals is contained in a cyclotomic field.
- Every abelian extension of the rationals is contained in a quadratic field.
- Every abelian extension of the rationals is contained in a cubic field.
- Every abelian extension of the rationals is contained in a quartic field.
Question 11 Multiple Choice (Single Answer)
What is the Hilbert irreducibility theorem?
- Every polynomial with integer coefficients that is irreducible over the rationals is also irreducible over the integers.
- Every polynomial with rational coefficients that is irreducible over the rationals is also irreducible over the integers.
- Every polynomial with real coefficients that is irreducible over the rationals is also irreducible over the integers.
- Every polynomial with complex coefficients that is irreducible over the rationals is also irreducible over the integers.
Question 12 Multiple Choice (Single Answer)
What is the Artin-Whaples theorem?
- Every finite Galois extension of the rationals is solvable.
- Every finite Galois extension of the rationals is solvable by radicals.
- Every finite Galois extension of the rationals is solvable by elementary functions.
- Every finite Galois extension of the rationals is solvable by algebraic functions.
Question 13 Multiple Choice (Single Answer)
What is the Galois correspondence?
- A bijection between the subgroups of the Galois group of a Galois extension and the subfields of the extension.
- A bijection between the subgroups of the Galois group of a Galois extension and the quotient fields of the extension.
- A bijection between the subgroups of the Galois group of a Galois extension and the subrings of the extension.
- A bijection between the subgroups of the Galois group of a Galois extension and the ideals of the extension.
Question 14 Multiple Choice (Single Answer)
What is the inverse Galois problem?
- Given a group, construct a Galois extension whose Galois group is isomorphic to the given group.
- Given a group, construct a field extension whose Galois group is isomorphic to the given group.
- Given a group, construct a ring extension whose Galois group is isomorphic to the given group.
- Given a group, construct a module extension whose Galois group is isomorphic to the given group.