المرجع الالكتروني للمعلوماتية
المرجع الألكتروني للمعلوماتية

الرياضيات
عدد المواضيع في هذا القسم 9761 موضوعاً
تاريخ الرياضيات
الرياضيات المتقطعة
الجبر
الهندسة
المعادلات التفاضلية و التكاملية
التحليل
علماء الرياضيات

Untitled Document
أبحث عن شيء أخر

مركبات النكهة Flavor Compounds
3-5-2018
حائل "كولومي" Coulomb barrier
10-7-2018
التعريف بالنظام التأديبي في الوظيفة العامة
16-6-2021
قلب المادة
2023-02-23
هل تمتلك الحشرات جهاز داخلي مميز؟
1-1-2021
مدرك قاعدة اليد امارة الملك
2024-08-04

Albert Cyril Offord  
  
76   01:09 مساءً   date: 12-10-2017
Author : W K Hayman
Book or Source : Albert Cyril Offord. 9 June 1906 - 4 June 2000, Biogr. Mems Fell. R. Soc. 48
Page and Part : ...


Read More
Date: 25-10-2017 10
Date: 22-10-2017 20
Date: 9-11-2017 18

Born: 9 June 1906 in London, England

Died: 4 June 2000 in Oxford, England


Cyril Offord's parents were Hester Louise and Albert Edwin Offord. Albert was a master printer with the publishing firm Eyre and Spottiswoode. Hester trained as an opera singer but after marrying Albert she gave up her plans to become a professional singer. Cyril was the eldest of his parents' three children, having two younger brothers Horace and Frank who both made careers in medicine. The family were Plymouth Brethrens, members of a Christian church with no distinction between clergy and laity. The family took part in the regular Sunday morning meetings and, later in life, Cyril recalled his unhappy memories of these meetings [1] (or [2]):-

... he was so bitter about his narrow Plymouth Brethren upbringing that he did not like to talk about his early years.

When he became older he renounced all religion, a position he held for most of his life, but we will mention his religious conversion towards the end of this biography. Offord was brought up in London where he attended Hackney Downs Grammar School.

After graduating from the Grammar School, Offord entered University College, London, where he studied mathematics. After the award of his first degree, he went to St John's College, Cambridge to undertake research. At Cambridge he came under the influence of J E Littlewood, who had been appointed as Rouse Ball Professor at Cambridge in 1928, and G H Hardy who had held the Sadleirian chair at Cambridge from 1931. He began publishing papers in 1932 with On the summability of power series and On the summability of trigonometric series appearing in that year and the paper Fourier and Hankel transformsin the following year. During his early years at Cambridge he collaborated with several mathematicians: Stephen Bosanquet, Einar Hille and Jacob David Tamarkin. In July 1936 he attended the International Congress of Mathematicians in Oslo and gave the lecture The uniqueness of the representation of a function by a trigonometric integral which was published in the Proceeding of the conference in the following year.

Offord had strong left-wing views and he had [3]:-

... a strong sense of social justice. In the 1930s, he belonged to Science For Peace and was in at the early stages of the Academic Assistance Council, now the Council for the Aid of Refugee Academics ...

He was elected a fellow of St John's College, Cambridge in 1937 and remained in Cambridge for three further years, leaving in 1940 to take up a temporary assistant lectureship at University College, Bangor. It was during these last three years at Cambridge that he worked with J E Littlewood on the topic for which he is best known today, and they published a series of important joint papers beginning with On the number of real roots of a random algebraic equation in 1938. In the following year they published a second paper with this title and in it they give estimates of the expected number of real roots for an equation of degree n when the coefficients are identically distributed random variables.

After spending two years in Bangor, Offord was appointed as a lecturer at King's College, Newcastle upon Tyne, in 1942. The University of Newcastle had been founded in 1937 as King's College, created from two Colleges of the University of Durham, namely Armstrong College and the College of Medicine, which were in Newcastle. Only in 1963 did King's College become the University of Newcastle with a charter making it independent of the University of Durham [1]:-

In Newcastle, Cyril met Margaret Yvonne Pickard, known as Rita, and they were married in 1945. Rita had been in the English Department at Newcastle, teaching and doing research on Early English texts. She gave up teaching upon marriage but continued with research, publishing two texts in the Early English Text Society. Their daughter, Margaret, was born in 1949 and has had a career in publishing, distance learning and educational technology.

In 1945, the year he was married, Offord was appointed as Professor of Pure Mathematics at Newcastle. On 4 March 1946 he was elected a fellow of the Royal Society of Edinburgh. He was proposed by Sir Edmund T Whittaker, John W Heslop Harrison, Alexander C Aitken, and Alfred D Hobson.

Werner Rogosinski was appointed as a lecturer in Newcastle in 1945 and promoted to reader in 1947. In January of the same year Offord appointed Walter Hayman who describes in [1] (or [2]) how he was treated with great kindness by Offord:-

To me Cyril and Rita could not have been kinder. They took me to live with them in their house in Whitley Bay until they had helped me to find suitable lodgings. Cyril gave me a very light teaching load, which left me plenty of time for research. On one day in the week I had just one lecture and asked Cyril whether it was really worth travelling down from the coast for that. He might reasonably have bitten my head off, but just replied that it was necessary. Offord told me about his collaboration with Littlewood. At that stage they were just writing their big paper ('On the distribution of zeros and a-values of a random integral function'). Littlewood made him change the draft several times, until finally it came back nearly to what it had been in the first instance. He advised me to do my research with a pencil having a rubber at the end, and I have stuck to this method of working ever since.

We should say a little more about the 'big paper' referred to by Hayman in this quotation. In it Offord and Littlewood considered the family of entire functions of finite order obtained by introducing independent plus or minus signs, each with probability 1/2, in the Taylor series of a given function. R P Boas writes:-

They showed, roughly speaking, that the general behaviour of these entire functions, and in particular the distribution of their values, is almost always the same, being in fact determined by the modulus of the maximum term.

Offord produced a remarkable generalisation of the results of this paper in The distribution of the values of an entire function whose coefficients are independent random variables (1965).

Returning to our account of Offord's career, he left Newcastle in 1948 when appointed to a chair at Birkbeck College, London. He was elected a fellow of the Royal Society of London in 1952. In different circumstances, he may have remained at Birkbeck College for the rest of his career, but he had a disagreement with the university authorities over the mathematics degree and left Birkbeck in 1966 to take up a newly created mathematics chair at the London School of Economics. This had been established in response to the increasing demand for more sophisticated mathematics in the Social Sciences where expertise in statistics and computing were becoming necessary. In 1973 he retired from the London School of Economics but remained in London as a senior research fellow at Imperial College. The London School of Economics paid this tribute to him in [4]:-

Within the School he is perhaps better known for his kindness, his humanity and the care and effort that he has put into establishing Mathematics as a subject of serious study at the London School of Economics. ... The School has been fortunate in attracting such a humane and gifted man as its first Professor of Mathematics.

However, he did not remain in London, but returned to Oxford to spend the rest of his retirement [1] (or [2]):-

In 1980 the Offords moved to Oxford, where Rita had done her degree in English literature at Lady Margaret Hall. Cyril attended meetings and continued publishing until the 1990s. Although Cyril was in frail health and poor sight owing to the loss of an eye because of a tumour in the 1970s, he and Rita greatly enjoyed their retirement, receiving guests in their small north Oxford house, while Cyril indulged in his passions for early music (of which there are many concerts in Oxford), gardening and French literature, benefiting from the proximity of the Maison Française. He created a beautiful walled garden, making a particular feature of the high walls with climbing plants such as clematis and roses. In summer the area was a feast of crimson and purple. Although musical, Cyril had never learned to play an instrument. He took up the lute in his retirement, receiving lessons from Diana PoultonThe somewhat doleful strains of the lute seemed to fit in with the world-weariness that beset him in his later years.

In September 1994 he wrote to one of his former Ph.D. students who had just retired:-

... the first few years of retirement can be very pleasant and I hope your wife and yourself enjoy them fully. I have now reached 88 and things are not so pleasant when you get to that age. However, I have managed to re-write some of the work I did with Littlewood. It is now a bit more concise and I think easier to read.

Near the beginning of this biography we mentioned that for most of his life Offord had rejected religion but had a conversion late in life. The conversion was, in fact, very late in his life, occurring shortly before his death when confirmed into the Church of England by the Bishop of Oxford. However, Offord's wife had been a member of the Church of England and for many years they had attended services together.


 

Articles:

  1. W K Hayman, Albert Cyril Offord. 9 June 1906 - 4 June 2000, Biogr. Mems Fell. R. Soc. 48 (2002), 341-355.
  2. W K Hayman, Albert Cyril Offord, FRS, 1906-2000, Bull. London Math. Soc. 37 (2005), 933-946.
  3. W K Hayman, Cyril Offord, The Guardian (Wednesday 5 July 2000).
  4. Retirements: A C Offord, LSE Magazine No 46 (November 1973), 8.

 




الجبر أحد الفروع الرئيسية في الرياضيات، حيث إن التمكن من الرياضيات يعتمد على الفهم السليم للجبر. ويستخدم المهندسون والعلماء الجبر يومياً، وتعول المشاريع التجارية والصناعية على الجبر لحل الكثير من المعضلات التي تتعرض لها. ونظراً لأهمية الجبر في الحياة العصرية فإنه يدرّس في المدارس والجامعات في جميع أنحاء العالم. ويُعجب الكثير من الدارسين للجبر بقدرته وفائدته الكبيرتين، إذ باستخدام الجبر يمكن للمرء أن يحل كثيرًا من المسائل التي يتعذر حلها باستخدام الحساب فقط.وجاء اسمه من كتاب عالم الرياضيات والفلك والرحالة محمد بن موسى الخورازمي.


يعتبر علم المثلثات Trigonometry علماً عربياً ، فرياضيو العرب فضلوا علم المثلثات عن علم الفلك كأنهما علمين متداخلين ، ونظموه تنظيماً فيه لكثير من الدقة ، وقد كان اليونان يستعملون وتر CORDE ضعف القوسي قياس الزوايا ، فاستعاض رياضيو العرب عن الوتر بالجيب SINUS فأنت هذه الاستعاضة إلى تسهيل كثير من الاعمال الرياضية.

تعتبر المعادلات التفاضلية خير وسيلة لوصف معظم المـسائل الهندسـية والرياضـية والعلمية على حد سواء، إذ يتضح ذلك جليا في وصف عمليات انتقال الحرارة، جريان الموائـع، الحركة الموجية، الدوائر الإلكترونية فضلاً عن استخدامها في مسائل الهياكل الإنشائية والوصف الرياضي للتفاعلات الكيميائية.
ففي في الرياضيات, يطلق اسم المعادلات التفاضلية على المعادلات التي تحوي مشتقات و تفاضلات لبعض الدوال الرياضية و تظهر فيها بشكل متغيرات المعادلة . و يكون الهدف من حل هذه المعادلات هو إيجاد هذه الدوال الرياضية التي تحقق مشتقات هذه المعادلات.