I've not read all the comments, but i have a question/suggestion.

May it be that we are missign the coordinization of TIME and FUEL?

Let's make more simple:

10:00 AM : LONDON

11:00 AM : PARIS

12:AM : ROME

In this case TIME is not a "continous variable", it's discrete.

So, to be able to move to algebra to make calculus we need a function to move TIME frome discrete to continous, as we did with the POSTISIONS (cities).

EDIT: to clarify. TIME in the timesheet is only a set of values. We can call them TIME_A, TIME_B, TIME_C. We need to apply a coordinization to TIME and FUEL as well. I think that the misleading is that that function is identity.

So to answer Erik question:

F :: (A -> B) -> (FA -> FB)

i think A -> B is the lookup table itself.

Then FA -> FB is the function that allows to compute position from time in the algebric way.

In this way F, the coordinization, should be well defined.

P.S.: sorry if i mispelled somthing, but is the first time ever that i talk math in english

## Comments

## E2E: Brian Beckman and Erik Meijer - Co/Contravariance in Physics and Programming, 3 of n

I've not read all the comments, but i have a question/suggestion.

May it be that we are missign the coordinization of TIME and FUEL?

Let's make more simple:

10:00 AM : LONDON

11:00 AM : PARIS

12:AM : ROME

In this case TIME is not a "continous variable", it's discrete.

So, to be able to move to algebra to make calculus we need a function to move TIME frome discrete to continous, as we did with the POSTISIONS (cities).

EDIT: to clarify. TIME in the timesheet is only a set of values. We can call them TIME_A, TIME_B, TIME_C. We need to apply a coordinization to TIME and FUEL as well. I think that the misleading is that that function is identity.

So to answer Erik question:

F :: (A -> B) -> (FA -> FB)

i think A -> B is the lookup table itself.

Then FA -> FB is the function that allows to compute position from time in the algebric way.

In this way F, the coordinization, should be well defined.

P.S.: sorry if i mispelled somthing, but is the first time ever that i talk math in english

P.S.S.: sorry if i wrote a lot of rubbish.