Default type MUST be a string.

MUST support all XML Schema types defined in XForms: primitive, derived, defined in xforms, and from external schema.

MUST support placing types on elements.

MUST support placing types on attributes.

Default value MUST be false if no calculate property is present.

Default value MUST be true if a calculate property is present.

readonly MUST support any legal XPath boolean expression that is convertible to boolean.

The readonly property of a node MUST be dynamic (updated when dependencies change).

If an ancestor of a node is readonly, the node MUST be readonly as well.

Default value MUST be false.

required MUST support any legal XPath boolean expression that is convertible to boolean.

The required property of a node MUST be dynamic (updated when dependencies change).

Ancestor nodes MUST have no effect on whether a node is required.

A control bound to a required node with xsi:nil=true MUST evaluate as invalid during revalidation *regardless* of the element value.

A control bound to a required node with a value that is not convertible to a non-empty string MUST evaluate as invalid during revalidation.

Controls bound to required nodes MAY indicate that the control is required.

Controls bound to required, irrelevant nodes MAY indicate that the control would be required if made relevant.

Controls bound to non-required nodes MAY indicate that the control is optional.

Controls bound to required nodes MAY provide immediate feedback including limited navigation.

Default value MUST be true.

relevant MUST support any legal XPath boolean expression that is convertible to boolean.

The relevant property of a node MUST be dynamic (updated when dependencies change).

If an ancestor of a node is relevant, the node MUST be relevant as well.

When true, associated form controls MUST be made available.

When false, associated form controls SHOULD be made unavailable, removed from navigation order, and not allowed focus.

After a recalculate, the value of the node must be the result of the XPath expression.

The calculate property of a node MUST be dynamic (updated when dependencies change).

Default value MUST be true.

constraint MUST support any legal XPath boolean expression that is convertible to boolean.

The constraint property of a node MUST be dynamic (updated when dependencies change).

The node MUST evaluate as invalid during revalidation if its constraint expression returns false.

XML Schema facets MUST be associated with a model item using an XML Schema, xsi:type or the type attribute in a bind element.

If multiple type constraints apply to a model item, only the first, in document order, MUST be applied.