1 | initial version |

When you do `A(x)`

, it uses the method `A.__call__(x)`

, so you can get help by evaluating `A.__call__?`

. For both of these algebras, this turns out to be the same method (both inherited from another class), which tries to coerce the argument `x`

into `A`

. In the case of `H`

, `H.basis().keys()[1]`

returns a matrix, and apparently there is a coercion map from matrices to `H`

. In the case of `A`

, you get a string, and there is no predefined way to coerce strings to elements of `A`

.

For `A`

, as you note, you can use `A.monomial(x)`

, but I think the preferred method is `A.term(x)`

. Look at its documentation; it constructs an element of `A`

corresponding to the basis element indexed by `x`

.

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