May be that my language is not perfect, so I try to better explain what I want to say, without using bad words (that is a peculiarity of Ventolin, may be he knows that way to expression only...).
For calculating what an athlete can run in a LONGER event, basing the calculation on the performance in a SHORTER event, we must know 2 things :
a) The REAL type of training used at the moment
b) The ability in ADAPTATION to the new requirements for the new distance.
For example, if an athlete is able to improve his PB in HM during a REAL preparation for the Marathon, it means that can run a marathon very fast ; but, IF WE LOOK AT THE PB IN HM AS MARK FOR HIS FULL MARATHON WITHOUT KNOWING HIS REAL TRAINING, the HM is completely useless. We have the example of Zersenay Tadesse : if he CAN (we don't know) and WANT to become a Marathon runner, probably he needs to change completely his training, BECAUSE IT'S NOT POSSIBLE RUNNING THE WR IN HM WITH THE LAST 10 KM IN 27:20 IF YOU DON'T PREPARE HM IN SPECIFIC WAY, and if you use a lot of specific speed you are not able to modify your metabolism in order to reduce the consumption of glycogen, that is the reason because an athlete can last at high speed for 42 km.
And, because every athlete is a different ANIMAL, we cant be sure that everybody can have the attitude for lasting at fast speed longer than 2 hours. So, to use mathematics in athletics is an exercise that cannot give correct informations.
I remember that, some year ago, a group of scientists (specialists in mathematics) made a study talking about the fact that, in 30 years, WOMEN had to overtake the MEN in Marathon. This ABSURD was based on the speed of the improvement in the WR, men and women. But, if we don't know that Marathon is something older than 110 years for men, and only 35 years for women, we cant have any information from the evolution of the WR. In fact, today (2010), nobody is able running like Ingrid Kristiansen and Joan Benoit in 1985...
Other scientists, at the beginning of 1970, made a calculation of the age average for all the Olympic finalists (from 1948 to 1968) in 100m, that was about 22 years, concluding that, after that age, the specific attitudes of a sprinter (reaction, explosivity, elasticity, flexibility, rapidity, etc...) went to decrease. So, they confused a situation depending on SOCIAL FACTORS (at that time, athletics was an activity not professional, no money, the best sprinters were students in US Universities and, finishing their education at the age of 22, had to quit their activity looking for a job) with a PHYSIOLOGICAL phenomen. If they knew T&F, they could know that, for example, one of the US runners in the relay 4x100 winning OG '72 was Mel Pender, 37 years old ; that Mike Larrabee won 400m in Tokyo '64 when was 32 ; that in the past Lord Burghley and in Italy Carlo Facelli were able running 400 HS at top level when were 35 (Facelli still good at 40 !).
NEVER a women can beat a WR of a men in any events. This for a very simple reason : there are big differences in morphology, physiology, muscular strenght, BECAUSE MEN AND WOMEN ARE DIFFERENT ANIMALS in the human race.
There are 2 types of science :
a) The science that can study the PHENOMEN (in this case the goal is TO EXPLAIN WHAT HAPPENS, but the phenomen is at the center of everything)
b) The science that can BUILD THE PHENOMEN (in this case what happens depends on the previous scientific preparation, that is the BASE for the development of the action)
In Italian (I don't have here an English dictionary, so I cant be correct in this for me difficult explanation), the first type of Science is called "Sperimentale" (because can study what already exists), the second type is called "Induttiva" (because can create something new based on the knowledge of the theory). For example, the MEDICINE is a science "Sperimentale" : can only study what already exists (REAL ACTION like base for THEORY). Mathematics is a science "Induttiva" : scientists send around the Moon a shuttle basing its route on a calculation (THEORY base of REAL ACTION).
In this situation, Athletics is a science "sperimentale", nothing to do with mathematics.
Sorry if can be difficult to understand my thought. I hope that somebody can explain in good English what I try to explain, and in any case I think that my concept is clear.
About Mary Keitany, never I speak about WR in Marathon. I cant exclude this after 4-5 years, but frankly it seems to me very far from the possibility of every athlete of today. Paula Radcliffe had a PB of 8'22" in 3000m, very far from the possibility of Mary, that, in my opinion, is more talented for long distances than Paula. Paula was a product of an incredible period of continuity, with an unbelievable concentration and a life totally dedicated to athletics. Under this point of view, there are no African athletes able to have the same level of application.
Speaking about the WR, also we must remember that, when Paula ran 2:15:25, she competed in a race for women only, using male pacers (and now it's not possible to repeat the same escamotage). I had personally 4 pacers in that race. The pacers had to finish the race, and that year the London Marathon had an official classification like 2 different competitions (as on track when we have race 1 and race 2). Of course, from that situation there was some advantage, also if Paula always showed great ability in running in front, against time.
In any case, speaking about 2:15 is, at the moment, something useless. Mary has a big talent : we will try to educate this talent in the best way, and at the end results will speak about what she and our technical management are able to do.