[Tutor] equality check difference

[Peter Otten]

Peter Otten wrote:

> In mathematics there is a property called "transitivity" which basically
> says that an operation op is transitive if from
> 
> (a op b) and (a op c)
> 
> follows
> 
> b op c

I opened the wikipedia article for the english word, but didn't start 
reading it until after I had hit send :( 
The above should be 

from 

(a op b) and (b op c) 

follows

(a op c)

For equality this doesn't matter, but for other operations, e. g.

a > b and b > c --> a > c

but not

WRONG! a > b and a > c --> b > c