The verify procedure is a semi-Boolean valued procedure that checks a relationship between two objects a and b. By default, the relationship checked is simple equality (evalb).  When verification ver is specified, true is returned in the case where the relationship exists. Otherwise a negative result in a standard form is returned (see type/verify).

When ver is specified as a set of verifications, the value returned is true when a and b satisfy the relation for any one of the verifications in the set. Otherwise, false is returned.

A verification ver is said to be symmetric if it is true that verify(a, b, ver) = verify(b, a, ver) for all possible values a and b.  The two argument form of verify is symmetric since it is true that $\mathrm{evalb}\left(a=b\right)$ if and only if $\mathrm{evalb}\left(b=a\right)$.

In addition to the structured verifications (see verify/structured), the following verification names are defined in Maple:

In addition, the three trivial verifications true, false, and FAIL will always return that result.

Note:  If a verification name is an operator, it must be back-quoted to prevent a syntax error.  See the examples below.

For more information, see verify/datatype, where datatype is one of the names in the above list.

In Maple, some objects return a different result from what may be expected when compared with evalb. For example, 0 and 0. compare equally under evalb, but [0] and [0.] do not.

For information on using structured verification expressions, see verify/structured.

$\mathrm{verify}\left(23\,5\,\mathrm{greater\_than}\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\mathrm{Array}\left(1..3\,\left[1\,2\,3\right]\right)\,\mathrm{Array}\left(\left[1\,2\,3\right]\,\mathrm{readonly}\right)\,\mathrm{Array}\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\left[a\,b\,x\left(x-1\right)\right]\,\left[a\,b\,x^2-x\right]\,'\mathrm{list}'\right)$

$\mathrm{false}$

$\mathrm{verify}\left(\left[a\,b\,x\left(x-1\right)\right]\,\left[a\,b\,x^2-x\right]\,'\mathrm{list}'\left('\mathrm{expand}'\right)\right)$

$\mathrm{true}$

$\mathrm{evalb}\left(\min \left(a\,b\,x\left(x-1\right)\right)=\min \left(a\,b\,x^2-x\right)\right)$

$\mathrm{false}$

$\mathrm{verify}\left(\min \left(a\,b\,x\left(x-1\right)\right)\,\min \left(a\,b\,x^2-x\right)\,'\mathrm{as\_list}'\left('\mathrm{expand}'\,'\min '\right)\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\left\{2\,3\,4\,4^{\frac{1}{2}}+3\right\}\,\left\{1\,2\,3\,4\,5\right\}\,'\mathrm{`subset`}'\left('\mathrm{simplify}'\right)\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\left[\mathrm{true}\,9^{\frac{1}{2}}\,\left(x+1\right)\left(x-1\right)\right]\,\left[\mathrm{true}\,3\,x^2-1\right]\,\left[\mathrm{boolean}\,\mathrm{simplify}\,\mathrm{normal}\right]\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\left\{2.203\,2.205\,3.375\,9.23\right\}\,\left\{2.204\,3.374\,9.231\right\}\,'\mathrm{set}'\left('\mathrm{float}'\left({10}^6\right)\right)\right)$

$\mathrm{true}$

$\mathrm{evalb}\left(\mathrm{undefined}=\mathrm{undefined}\right)$

$\mathrm{true}$

$\mathrm{evalb}\left(\left[\mathrm{undefined}\right]=\left[\mathrm{undefined}\right]\right)$

$\mathrm{true}$

$\mathrm{verify}\left(\left[\mathrm{undefined}\right]\,\left[\mathrm{undefined}\right]\,'\mathrm{list}'\right)$

$\mathrm{true}$

$\mathrm{evalb}\left(0=0.\right)$

$\mathrm{true}$

$\mathrm{evalb}\left(\left\{0\right\}=\left\{0.\right\}\right)$

$\mathrm{false}$

$\mathrm{verify}\left(\left\{0\right\}\,\left\{0.\right\}\,'\mathrm{set}'\right)$

$\mathrm{true}$