Dr Eugenia Cheng is a Senior Lecturer of Pure Mathematics at the University of Sheffield. She grew up in Sussex, and holds three degrees from the University of Cambridge. After completing post-doctoral work at the Universities of Cambridge, Chicago and Nice, she took up her current post at the University of Sheffield. She has published articles in eight different journals and given talks in 14 different countries. Dr Cheng is known for her communication skils both in the research community and in teaching. She was an early pioneer of YouTube lectures, beginning in 2007, and her videos have been viewed around 700,000 times to date (May 2013).
This video was a shortlisted application to one of the BBC's Expert Women's Day events, which offer free training to female specialists who would like to appear in the media as contributors and presenters. Find out more about the initiative and see other expert's videos at the Expert Women's Day YouTube channel or the BBC Academy website www.bbc.co.uk/academy.Infinity 3TheMathsters2012-06-05 | Introducing the idea of infinity as "the number of natural numbers" and a first look at Hilbert's hotel.Infinity 2TheMathsters2012-06-05 | More problems that arise if we try and use infinity as a "number", with addition. Introducing the idea of going back doing arithmetic by "thinking" about it.Infinity 1TheMathsters2012-06-04 | What is infinity? A first look at how we can think about infinity, and some problems that arise if we try and use infinity as a "number".Induction 13TheMathsters2011-11-02 | Proof by induction that if alpha + 1/alpha is an integer, then alpha^n + 1/alpha^n is an integer, for all natural numbers n.Functions 5TheMathsters2011-02-09 | More examples with more formal proofs of injectivity and surjectivity, and proofs that functions are not injective and surjectiveFunctions 4TheMathsters2011-02-09 | Looking at some examples of functions to see if they are injective and surjective, introducing bijective functions at the endFunctions 3TheMathsters2011-01-31 | Introduction of injective and surjective functions, with definition at the endFunctions 1TheMathsters2010-11-16 | Definition of function and a few examplesFunctions 2TheMathsters2010-11-16 | Some more examples of functions, definition of composition, proof that composition is associative.Numbers 16TheMathsters2010-10-26 | Using Euclid's algorithm backwards to show that if hcf(x,y)=h, not necessarily 1, we can get an expression rx+sy=hNumbers 14TheMathsters2010-10-26 | Using Euclid's algorithm backwards to show that if hcf(x,y)=1 we can get an expression rx+sy=1Numbers 15TheMathsters2010-10-26 | Another example of Euclid's algorithm backwards to show that if hcf(x,y)=1 we can get an expression rx+sy=1Numbers 13TheMathsters2010-10-18 | Proof of the converse to the result in Numbers 13: that if "p|ab implies p|a or p|b" then p must be prime.Numbers 12TheMathsters2010-10-18 | Introducing prime numbers as "p|ab implies p|a or p|b" and the beginnings of a proof that prime numbers have this propertyNumbers 11TheMathsters2010-10-11 | Proof that any natural number greater than 1 can be written as a product of primes (we don't do uniqueness here). Two proofs -- one by strong induction and one using well-ordering.Numbers 10TheMathsters2010-10-11 | Proof that there is an infinite number of primes, assuming that every number has at least one prime factor. Small mind block in the middle...Numbers 9TheMathsters2010-10-04 | Finishing off the Sieve of Eratosthenes to find all the prime numbers up to 100, brief discussion of Mersenne primes and largest prime number currently known to manNumbers 8TheMathsters2010-10-04 | Testing a few numbers to see if they're prime, and a first look at the Sieve of Eratosthenes to find all the prime numbers up to 100Numbers 7TheMathsters2010-10-04 | Introduction to prime numbers, some examples of factorising numbers into primes uniquely, basic definition of prime numbersSets 14TheMathsters2010-09-28 | Inclusion-exclusion principle for a union of four sets.Sets 13TheMathsters2010-09-28 | Introducing the inclusion-exclusion principle for counting the elements in a union of two sets and a union of three setsEquivalence relations 3TheMathsters2010-09-20 | Proof that an equivalence relation on a set S partitions S into equivalence classesEquivalence relations 4TheMathsters2010-09-20 | Example of equivalence classes for congruence mod 5, and a mention of representativesEquivalence relations 2TheMathsters2010-04-30 | Formal definition, and example of congruence mod 5. Introduction of the idea of equivalence classesEquivalence relations 1TheMathsters2010-04-30 | Introducing equivalence relations with some examples using relationships between peopleModular arithmetic 7TheMathsters2010-03-30 | Square roots in modular arithmeticModular arithmetic 6TheMathsters2010-03-30 | Comparing highest common factor and lowest common multiple.Modular arithmetic 5TheMathsters2010-03-19 | For musicians: using lowest common multiples to work out how cross-rhythms goModular arithmetic 4TheMathsters2010-03-19 | Another example of the Chinese Remainder Theorem, and an explanation of how its different if the two numbers arent coprimeModular arithmetic 3TheMathsters2010-03-12 | Some basic simultaneous equations in modular arithmetic, and introduction to the Chinese Remainder TheoremModular arithmetic 2TheMathsters2010-03-12 | A first look at equations mod n, adding a number to both sides, multiplying both sides by a numberInduction 12TheMathsters2010-03-05 | Principle of strong induction implies Well-Ordering of the natural numbersModular arithmetic 1TheMathsters2010-03-05 | Introduction to modular arithmetic using clocks and telling the timeInduction 11TheMathsters2010-03-05 | Well-ordering implies the Principle of InductionInduction 10TheMathsters2010-03-05 | The principle of induction, the principle of strong induction and the well-ordering principleInduction 9TheMathsters2010-03-05 | Proof by induction that all cows are the same colour. What's gone wrong?Induction 8TheMathsters2009-12-04 | Proof by induction that if S is a set with n elements, then the power set of S has 2^n elements.Induction 7TheMathsters2009-12-04 | Proof byinduction that 3.4^n + 4.11^n is divisible by 7 for all natural numbers n.Induction 6TheMathsters2009-12-04 | Proof by induction of what the sum of the first n cubes isInduction 5TheMathsters2009-12-01 | Proof by induction that n^3 n is always divisible by 3. Also direct proof of this and the previous example, for comparison.Induction 4TheMathsters2009-12-01 | Proof by induction that n^2 + n is always evenInduction 3TheMathsters2009-11-27 | Proof by induction that 1+2+...+n = n(n+1)/nInduction 2TheMathsters2009-11-27 | Finishing the the proof by induction that there are n! ways of ordering the numbers 1,2,3,...n. Introducing the next example: 1+2+...+nInduction 1TheMathsters2009-11-27 | Introduction to proof by induction, example of ordering the numbers 1,2,3,...,nNumbers 6TheMathsters2009-11-20 | Explanation of why Euclids algorithm worksNumbers 5TheMathsters2009-11-20 | Introducing Euclids algorithm for finding highest common factors, with a couple of examplesNumbers 4TheMathsters2009-11-10 | Introducing highest common factors (=greatest common divisor)Numbers 3TheMathsters2009-11-10 | Divisibility formally, and proof that if m and n are divisible by d then so is m+n