TMCL Regexp constraint

Hi,

I am wondering how the TMCL Regular Expression constraint [1] should  
be applied:

a. the boundaries are implicit
b. the boundaries are explicit

E.g. i want all lower case characters in my string:

Should the value of the respective occurrence of the topic that  
represents my regexp constraint be:
a. [a-z]+
b. ^[a-z]+$

 From the example that is given in the TMCL spec [1], i would guess a.

Best,

Robert

[1] http://isotopicmaps.org/tmcl/tmcl.html#sect-regexp-constraint