x * y = y * x # label(commutativity). x * c != e # answer(x) # label("the denial"). -p(c) | -q(c) # answer("here it is"). a * b != b * a # action(in_proof -> exit) # answer(commutativity). x * (y * z) = y * (x * z) # bsub_hint_wt(500).Each attribute has a data type of string, integer, or term. A string attribute is really just a term attribute that is a constant. If a string attribute is not a legal constant, it can be enclosed in double quotes to make it so.
The accepted attributes are shown in the following table.
Name | Type | Inheritable | Purpose |
---|---|---|---|
label | string | No | Comment |
answer | term | Yes | Record substitutions and what has been proved |
action | term | No | Triggers action when clause is used |
bsub_hint_add_wt | integer | No | Used for hints |
bsub_hint_wt | integer | No | Used for hints |
Inheritable attributes are passed from parent to child during most inference rules.
Answer attributes (like all other attributes) contain exactly one argument. If you wish to record substitutions for more than one variable, you must use a term that contains all of the variables, for example, a list, as in the following clause.
-p(c,x,y,z) # answer([x,y,z]).