Hello Steffi,

I am glad that this was useful. Your english is fine.

One of the difficult things about answering questions in this community is that the answer should be useful for a wide range of readers: simple answers for advanced users can be insulting; complicated answers for beginners are useless. My guess is that you are someplace in the spectrum.

I usually try to include a number of steps to lead the reader to a solution. This morning I was in a hurry and didn't....

So, here are different ways to do the same thing. As you can see, some are more readable than others; but having examples to study is useful, I think. I would advise to evaluate these lines one at a time instead of one big cell full of code.

tickPositions = FindDivisions[{Log[10, .001], Log[10, 1000]}, 8]

tickLabels = 10^tickPositions

tickStructure = Table[{tickPositions[[i]], tickLabels[[i]]}, {i, 1, Length[tickPositions]}]

tickStructure = Transpose[{tickPositions, tickLabels}]

tickStructure =

Map[{#, 10^#} &, FindDivisions[{Log[10, .001], Log[10, 1000]}, 8]]

tickStructure =

Thread[({#, 10^#} &)[

FindDivisions[{Log[10, .001], Log[10, 1000]}, 8]]]

Finally, looking at this with the names and refering to Details in Ticks in the help browser will help you see what is going on.

Plot3D[(10^x - 10^y)/(1 + 10^x*10^y), {x, Log[10, .001],

Log[10, 1000]}, {y, Log[10, .001], Log[10, 1000]},

PlotRange -> All,

Ticks -> {

tickStructure,

tickStructure,

Automatic} ]

My general advice when you see code posted here that is mysterious is to work from the inside out. Copy what Ticks is pointing to, evaluate it, and then look and see what kind of structure that Ticks is looking for.

I hope this helps.

Kind regards, Craig