@Markiyan Hirnyk 

I just did, thank you for the suggestion.

Thanks, that answers all my questions on this issue (can't vote up :). As is demonstrated in the convert,local help: what you see is not what you might think naively (i.e., a is not necessarily equal to a).

Thanks, that answers all my questions on this issue (can't vote up :). As is demonstrated in the convert,local help: what you see is not what you might think naively (i.e., a is not necessarily equal to a).

Kamel, thank you for your response.

So if I understand correctly, there is no way to change the 'a' in expr2 to a certain value, if one changes the assumptions of 'a' after defining expr2? Hence one must make all assumptions either before or after an expression but not both before and after? It becomes an inaccesible local variable otherwise? Or is there any other way to still have access to it (I seem to be missing the underlying reason for this behaviour)?

The reason that I used the assumptions in a flexible way is that I started with a general case and then make more and more assumptions as I go along to get to a specific case.

Kamel, thank you for your response.

So if I understand correctly, there is no way to change the 'a' in expr2 to a certain value, if one changes the assumptions of 'a' after defining expr2? Hence one must make all assumptions either before or after an expression but not both before and after? It becomes an inaccesible local variable otherwise? Or is there any other way to still have access to it (I seem to be missing the underlying reason for this behaviour)?

The reason that I used the assumptions in a flexible way is that I started with a general case and then make more and more assumptions as I go along to get to a specific case.